oracle常用经典SQL查询
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1 常用SQL查询: 2 3 1、查看表空间的名称及大小 4 5 select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size 6 from dba_tablespaces t, dba_data_files d 7 where t.tablespace_name = d.tablespace_name 8 group by t.tablespace_name; 9 10 2、查看表空间物理文件的名称及大小 11 12 select tablespace_name, file_id, file_name, 13 round(bytes/(1024*1024),0) total_space 14 from dba_data_files 15 order by tablespace_name; 16 17 3、查看回滚段名称及大小 18 19 select segment_name, tablespace_name, r.status, 20 (initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent, 21 max_extents, v.curext CurExtent 22 From dba_rollback_segs r, v$rollstat v 23 Where r.segment_id = v.usn(+) 24 order by segment_name; 25 26 4、查看控制文件 27 28 select name from v$controlfile; 29 30 5、查看日志文件 31 32 select member from v$logfile; 33 34 6、查看表空间的使用情况 35 36 select sum(bytes)/(1024*1024) as free_space,tablespace_name 37 from dba_free_space 38 group by tablespace_name; 39 40 SELECT A.TABLESPACE_NAME,A.BYTES TOTAL,B.BYTES USED, C.BYTES FREE, 41 (B.BYTES*100)/A.BYTES "% USED",(C.BYTES*100)/A.BYTES "% FREE" 42 FROM SYS.***$TS_***AIL A,SYS.***$TS_USED B,SYS.***$TS_FREE C 43 WHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME AND A.TABLESPACE_NAME=C.TABLESPACE_NAME; 44 45 7、查看数据库库对象 46 47 select owner, object_type, status, count(*) count# from all_objects group by owner, object_type, status; 48 49 8、查看数据库的版本 50 51 Select version FROM Product_component_version 52 Where SUBSTR(PRODUCT,1,6)=‘‘Oracle‘‘; 53 54 9、查看数据库的创建日期和归档方式 55 56 Select Created, Log_Mode, Log_Mode From V$Database; 57 58 10、捕捉运行很久的SQL 59 60 column username format a12 61 column opname format a16 62 column progress format a8 63 64 select username,sid,opname, 65 round(sofar*100 / totalwork,0) || ‘‘%‘‘ as progress, 66 time_remaining,sql_text 67 from v$session_longops , v$sql 68 where time_remaining <> 0 69 and sql_address = address 70 and sql_hash_value = hash_value 71 / 72 11。查看数据表的参数信息 73 SELECT partition_name, high_value, high_value_length, tablespace_name, 74 pct_free, pct_used, ini_trans, max_trans, initial_extent, 75 next_extent, min_extent, max_extent, pct_increase, FREELISTS, 76 freelist_groups, LOGGING, BUFFER_POOL, num_rows, blocks, 77 empty_blocks, ***g_space, chain_cnt, ***g_row_len, sample_size, 78 last_analyzed 79 FROM dba_tab_partitions 80 --WHERE table_name = :tname AND table_owner = :towner 81 ORDER BY partition_position 82 83 12.查看还没提交的事务 84 select * from v$locked_object; 85 select * from v$transaction; 86 87 13。查找object为哪些进程所用 88 select 89 p.spid, 90 s.sid, 91 s.serial# serial_num, 92 s.username user_name, 93 a.type object_type, 94 s.osuser os_user_name, 95 a.owner, 96 a.object object_name, 97 decode(sign(48 - command), 98 1, 99 to_char(command), ‘‘Action Code #‘‘ || to_char(command) ) action, 100 p.program oracle_process, 101 s.terminal terminal, 102 s.program program, 103 s.status session_status 104 from v$session s, v$access a, v$process p 105 where s.paddr = p.addr and 106 s.type = ‘‘USER‘‘ and 107 a.sid = s.sid and 108 a.object=‘‘SUBSCRIBER_ATTR‘‘ 109 order by s.username, s.osuser 110 111 14。回滚段查看 112 select rownum, sys.dba_rollback_segs.segment_name Name, v$rollstat.extents 113 Extents, v$rollstat.rssize Size_in_Bytes, v$rollstat.xacts XActs, 114 v$rollstat.gets Gets, v$rollstat.waits Waits, v$rollstat.writes Writes, 115 sys.dba_rollback_segs.status status from v$rollstat, sys.dba_rollback_segs, 116 v$rollname where v$rollname.name(+) = sys.dba_rollback_segs.segment_name and 117 v$rollstat.usn (+) = v$rollname.usn order by rownum 118 119 15。耗资源的进程(top session) 120 select s.schemaname schema_name, decode(sign(48 - command), 1, 121 to_char(command), ‘‘Action Code #‘‘ || to_char(command) ) action, status 122 session_status, s.osuser os_user_name, s.sid, p.spid , s.serial# serial_num, 123 nvl(s.username, ‘‘[Oracle process]‘‘) user_name, s.terminal terminal, 124 s.program program, st.value criteria_value from v$sesstat st, v$session s , v$process p 125 where st.sid = s.sid and st.statistic# = to_number(‘‘38‘‘) and (‘‘ALL‘‘ = ‘‘ALL‘‘ 126 or s.status = ‘‘ALL‘‘) and p.addr = s.paddr order by st.value desc, p.spid asc, s.username asc, s.osuser asc 127 128 16。查看锁(lock)情况 129 select /*+ RULE */ ls.osuser os_user_name, ls.username user_name, 130 decode(ls.type, ‘‘RW‘‘, ‘‘Row wait enqueue lock‘‘, ‘‘TM‘‘, ‘‘DML enqueue lock‘‘, ‘‘TX‘‘, 131 ‘‘Transaction enqueue lock‘‘, ‘‘UL‘‘, ‘‘User supplied lock‘‘) lock_type, 132 o.object_name object, decode(ls.lmode, 1, null, 2, ‘‘Row Share‘‘, 3, 133 ‘‘Row Exclusive‘‘, 4, ‘‘Share‘‘, 5, ‘‘Share Row Exclusive‘‘, 6, ‘‘Exclusive‘‘, null) 134 lock_mode, o.owner, ls.sid, ls.serial# serial_num, ls.id1, ls.id2 135 from sys.dba_objects o, ( select s.osuser, s.username, l.type, 136 l.lmode, s.sid, s.serial#, l.id1, l.id2 from v$session s, 137 v$lock l where s.sid = l.sid ) ls where o.object_id = ls.id1 and o.owner 138 <> ‘‘SYS‘‘ order by o.owner, o.object_name 139 140 17。查看等待(wait)情况 141 SELECT v$waitstat.class, v$waitstat.count count, SUM(v$sysstat.value) sum_value 142 FROM v$waitstat, v$sysstat WHERE v$sysstat.name IN (‘‘db block gets‘‘, 143 ‘‘consistent gets‘‘) group by v$waitstat.class, v$waitstat.count 144 145 18。查看sga情况 146 SELECT NAME, BYTES FROM SYS.V_$SGASTAT ORDER BY NAME ASC 147 148 19。查看catched object 149 SELECT owner, name, db_link, namespace, 150 type, sharable_mem, loads, executions, 151 locks, pins, kept FROM v$db_object_cache 152 153 20。查看V$SQLAREA 154 SELECT SQL_TEXT, SHARABLE_MEM, PERSISTENT_MEM, RUNTIME_MEM, SORTS, 155 VERSION_COUNT, LOADED_VERSIONS, OPEN_VERSIONS, USERS_OPENING, EXECUTIONS, 156 USERS_EXECUTING, LOADS, FIRST_LOAD_TIME, INVALIDATIONS, PARSE_CALLS, DISK_READS, 157 BUFFER_GETS, ROWS_PROCESSED FROM V$SQLAREA 158 159 21。查看object分类数量 160 select decode (o.type#,1,‘‘INDEX‘‘ , 2,‘‘TABLE‘‘ , 3 , ‘‘CLUSTER‘‘ , 4, ‘‘VIEW‘‘ , 5 , 161 ‘‘SYNONYM‘‘ , 6 , ‘‘SEQUENCE‘‘ , ‘‘OTHER‘‘ ) object_type , count(*) quantity from 162 sys.obj$ o where o.type# > 1 group by decode (o.type#,1,‘‘INDEX‘‘ , 2,‘‘TABLE‘‘ , 3 163 , ‘‘CLUSTER‘‘ , 4, ‘‘VIEW‘‘ , 5 , ‘‘SYNONYM‘‘ , 6 , ‘‘SEQUENCE‘‘ , ‘‘OTHER‘‘ ) union select 164 ‘‘COLUMN‘‘ , count(*) from sys.col$ union select ‘‘DB LINK‘‘ , count(*) from 165 166 22。按用户查看object种类 167 select u.name schema, sum(decode(o.type#, 1, 1, NULL)) indexes, 168 sum(decode(o.type#, 2, 1, NULL)) tables, sum(decode(o.type#, 3, 1, NULL)) 169 clusters, sum(decode(o.type#, 4, 1, NULL)) views, sum(decode(o.type#, 5, 1, 170 NULL)) synonyms, sum(decode(o.type#, 6, 1, NULL)) sequences, 171 sum(decode(o.type#, 1, NULL, 2, NULL, 3, NULL, 4, NULL, 5, NULL, 6, NULL, 1)) 172 others from sys.obj$ o, sys.user$ u where o.type# >= 1 and u.user# = 173 o.owner# and u.name <> ‘‘PUBLIC‘‘ group by u.name order by 174 sys.link$ union select ‘‘CONSTRAINT‘‘ , count(*) from sys.con$ 175 176 23。有关connection的相关信息 177 1)查看有哪些用户连接 178 select s.osuser os_user_name, decode(sign(48 - command), 1, to_char(command), 179 ‘‘Action Code #‘‘ || to_char(command) ) action, p.program oracle_process, 180 status session_status, s.terminal terminal, s.program program, 181 s.username user_name, s.fixed_table_sequence activity_meter, ‘‘‘‘ query, 182 0 memory, 0 max_memory, 0 cpu_usage, s.sid, s.serial# serial_num 183 from v$session s, v$process p where s.paddr=p.addr and s.type = ‘‘USER‘‘ 184 order by s.username, s.osuser 185 2)根据v.sid查看对应连接的资源占用等情况 186 select n.name, 187 v.value, 188 n.class, 189 n.statistic# 190 from v$statname n, 191 v$sesstat v 192 where v.sid = 71 and 193 v.statistic# = n.statistic# 194 order by n.class, n.statistic# 195 3)根据sid查看对应连接正在运行的sql 196 select /*+ PUSH_SUBQ */ 197 command_type, 198 sql_text, 199 sharable_mem, 200 persistent_mem, 201 runtime_mem, 202 sorts, 203 version_count, 204 loaded_versions, 205 open_versions, 206 users_opening, 207 executions, 208 users_executing, 209 loads, 210 first_load_time, 211 invalidations, 212 parse_calls, 213 disk_reads, 214 buffer_gets, 215 rows_processed, 216 sysdate start_time, 217 sysdate finish_time, 218 ‘‘>‘‘ || address sql_address, 219 ‘‘N‘‘ status 220 from v$sqlarea 221 where address = (select sql_address from v$session where sid = 71) 222 223 24.查询表空间使用情况 224 select a.tablespace_name "表空间名称", 225 100-round((nvl(b.bytes_free,0)/a.bytes_alloc)*100,2) "占用率(%)", 226 round(a.bytes_alloc/1024/1024,2) "容量(M)", 227 round(nvl(b.bytes_free,0)/1024/1024,2) "空闲(M)", 228 round((a.bytes_alloc-nvl(b.bytes_free,0))/1024/1024,2) "使用(M)", 229 Largest "最大扩展段(M)", 230 to_char(sysdate,‘‘yyyy-mm-dd hh24:mi:ss‘‘) "采样时间" 231 from (select f.tablespace_name, 232 sum(f.bytes) bytes_alloc, 233 sum(decode(f.autoextensible,‘‘YES‘‘,f.maxbytes,‘‘NO‘‘,f.bytes)) maxbytes 234 from dba_data_files f 235 group by tablespace_name) a, 236 (select f.tablespace_name, 237 sum(f.bytes) bytes_free 238 from dba_free_space f 239 group by tablespace_name) b, 240 (select round(max(ff.length)*16/1024,2) Largest, 241 ts.name tablespace_name 242 from sys.fet$ ff, sys.file$ tf,sys.ts$ ts 243 where ts.ts#=ff.ts# and ff.file#=tf.relfile# and ts.ts#=tf.ts# 244 group by ts.name, tf.blocks) c 245 where a.tablespace_name = b.tablespace_name and a.tablespace_name = c.tablespace_name 246 247 25. 查询表空间的碎片程度 248 249 select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name 250 h***ing count(tablespace_name)>10; 251 252 alter tablespace name coalesce; 253 alter table name deallocate unused; 254 255 create or replace view ts_blocks_v as 256 select tablespace_name,block_id,bytes,blocks,‘‘free space‘‘ segment_name from dba_free_space 257 union all 258 select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents; 259 260 select * from ts_blocks_v; 261 262 select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space 263 group by tablespace_name; 264 265 26。查询有哪些数据库实例在运行 266 select inst_name from v$active_instances; 267 268 =========================================================== 269 ######### 创建数据库----look $ORACLE_HOME/rdbms/admin/buildall.sql ############# 270 271 create database db01 272 maxlogfiles 10 273 maxdatafiles 1024 274 maxinstances 2 275 logfile 276 GROUP 1 (‘‘/u01/oradata/db01/log_01_db01.rdo‘‘) SIZE 15M, 277 GROUP 2 (‘‘/u01/oradata/db01/log_02_db01.rdo‘‘) SIZE 15M, 278 GROUP 3 (‘‘/u01/oradata/db01/log_03_db01.rdo‘‘) SIZE 15M, 279 datafile ‘‘u01/oradata/db01/system_01_db01.dbf‘‘) SIZE 100M, 280 undo tablespace UNDO 281 datafile ‘‘/u01/oradata/db01/undo_01_db01.dbf‘‘ SIZE 40M 282 default temporary tablespace TEMP 283 tempfile ‘‘/u01/oradata/db01/temp_01_db01.dbf‘‘ SIZE 20M 284 extent management local uniform size 128k 285 character set AL32UTE8 286 national character set AL16UTF16 287 set time_zone=‘‘America/New_York‘‘; 288 289 ############### 数据字典 ########## 290 291 set wrap off 292 293 select * from v$dba_users; 294 295 grant select on table_name to user/rule; 296 297 select * from user_tables; 298 299 select * from all_tables; 300 301 select * from dba_tables; 302 303 revoke dba from user_name; 304 305 shutdown immediate 306 307 startup nomount 308 309 select * from v$instance; 310 311 select * from v$sga; 312 313 select * from v$tablespace; 314 315 alter session set nls_language=american; 316 317 alter database mount; 318 319 select * from v$database; 320 321 alter database open; 322 323 desc dictionary 324 325 select * from dict; 326 327 desc v$fixed_table; 328 329 select * from v$fixed_table; 330 331 set oracle_sid=foxconn 332 333 select * from dba_objects; 334 335 set serveroutput on 336 337 execute dbms_output.put_line(‘‘sfasd‘‘); 338 339 ############# 控制文件 ########### 340 341 select * from v$database; 342 343 select * from v$tablespace; 344 345 select * from v$logfile; 346 347 select * from v$log; 348 349 select * from v$backup; 350 351 /*备份用户表空间*/ 352 alter tablespace users begin backup; 353 354 select * from v$archived_log; 355 356 select * from v$controlfile; 357 358 alter system set control_files=‘‘$ORACLE_HOME/oradata/u01/ctrl01.ctl‘‘, 359 ‘‘$ORACLE_HOME/oradata/u01/ctrl02.ctl‘‘ scope=spfile; 360 361 cp $ORACLE_HOME/oradata/u01/ctrl01.ctl $ORACLE_HOME/oradata/u01/ctrl02.ctl 362 363 startup pfile=‘‘../initSID.ora‘‘ 364 365 select * from v$parameter where name like ‘‘control%‘‘ ; 366 367 show parameter control; 368 369 select * from v$controlfile_record_section; 370 371 select * from v$tempfile; 372 373 /*备份控制文件*/ 374 alter database backup controlfile to ‘‘../filepath/control.bak‘‘; 375 376 /*备份控制文件,并将二进制控制文件变为了asc 的文本文件*/ 377 alter database backup controlfile to trace; 378 379 ############### redo log ############## 380 381 archive log list; 382 383 alter system archive log start;--启动自动存档 384 385 alter system switch logfile;--强行进行一次日志switch 386 387 alter system checkpoint;--强制进行一次checkpoint 388 389 alter tablspace users begin backup; 390 391 alter tablespace offline; 392 393 /*checkpoint 同步频率参数FAST_START_MTTR_TARGET,同步频率越高,系统恢复所需时间越短*/ 394 show parameter fast; 395 396 show parameter log_checkpoint; 397 398 /*加入一个日志组*/ 399 alter database add logfile group 3 (‘‘/$ORACLE_HOME/oracle/ora_log_file6.rdo‘‘ size 10M); 400 401 /*加入日志组的一个成员*/ 402 alter database add logfile member ‘‘/$ORACLE_HOME/oracle/ora_log_file6.rdo‘‘ to group 3; 403 404 /*删除日志组:当前日志组不能删;活动的日志组不能删;非归档的日志组不能删*/ 405 alter database drop logfile group 3; 406 407 /*删除日志组中的某个成员,但每个组的最后一个成员不能被删除*/ 408 alter databse drop logfile member ‘‘$ORACLE_HOME/oracle/ora_log_file6.rdo‘‘; 409 410 /*清除在线日志*/ 411 alter database clear logfile ‘‘$ORACLE_HOME/oracle/ora_log_file6.rdo‘‘; 412 413 alter database clear logfile group 3; 414 415 /*清除非归档日志*/ 416 alter database clear unarchived logfile group 3; 417 418 /*重命名日志文件*/ 419 alter database rename file ‘‘$ORACLE_HOME/oracle/ora_log_file6.rdo‘‘ to ‘‘$ORACLE_HOME/oracle/ora_log_file6a.rdo‘‘; 420 421 show parameter db_create; 422 423 alter system set db_create_online_log_dest_1=‘‘path_name‘‘; 424 425 select * from v$log; 426 427 select * from v$logfile; 428 429 /*数据库归档模式到非归档模式的互换,要启动到mount状态下才能改变;startup mount;然后再打开数据库.*/ 430 alter database noarchivelog/archivelog; 431 432 achive log start;---启动自动归档 433 434 alter system archive all;--手工归档所有日志文件 435 436 select * from v$archived_log; 437 438 show parameter log_archive; 439 440 ###### 分析日志文件logmnr ############## 441 442 1) 在init.ora中set utl_file_dir 参数 443 2) 重新启动oracle 444 3) create 目录文件 445 desc dbms_logmnr_d; 446 dbms_logmnr_d.build; 447 4) 加入日志文件 add/remove log file 448 dhms_logmnr.add_logfile 449 dbms_logmnr.removefile 450 5) start logmnr 451 dbms_logmnr.start_logmnr 452 6) 分析出来的内容查询 v$logmnr_content --sqlredo/sqlundo 453 454 实践: 455 456 desc dbms_logmnr_d; 457 458 /*对数据表做一些操作,为恢复操作做准备*/ 459 update 表 set qty=10 where stor_id=6380; 460 461 delete 表 where stor_id=7066; 462 /***********************************/ 463 utl_file_dir的路径 464 execute dbms_logmnr_d.build(‘‘foxdict.ora‘‘,‘‘$ORACLE_HOME/oracle/admin/fox/cdump‘‘); 465 466 execute dbms_logmnr.add_logfile(‘‘$ORACLE_HOME/oracle/ora_log_file6.log‘‘,dbms_logmnr.newfile); 467 468 execute dbms_logmnr.start_logmnr(dictfilename=>‘‘$ORACLE_HOME/oracle/admin/fox/cdump/foxdict.ora‘‘); 469 470 ######### tablespace ############## 471 472 select * form v$tablespace; 473 474 select * from v$datafile; 475 476 /*表空间和数据文件的对应关系*/ 477 select t1.name,t2.name from v$tablespace t1,v$datafile t2 where t1.ts#=t2.ts#; 478 479 alter tablespace users add datafile ‘‘path‘‘ size 10M; 480 481 select * from dba_rollback_segs; 482 483 /*限制用户在某表空间的使用限额*/ 484 alter user user_name quota 10m on tablespace_name; 485 486 create tablespace xxx [datafile ‘‘path_name/datafile_name‘‘] [size xxx] [extent management local/dictionary] [default storage(xxx)]; 487 488 exmple: create tablespace userdata datafile ‘‘$ORACLE_HOME/oradata/userdata01.dbf‘‘ size 100M AUTOEXTEND ON NEXT 5M MAXSIZE 200M; 489 create tablespace userdata datafile ‘‘$ORACLE_HOME/oradata/userdata01.dbf‘‘ size 100M extent management dictionary default storage(initial 100k next 100k pctincrease 10) offline; 490 /*9i以后,oracle建议使用local管理,而不使用dictionary管理,因为local采用bitmap管理表空间 ,不会产生系统表空间的自愿争用;*/ 491 create tablespace userdata datafile ‘‘$ORACLE_HOME/oradata/userdata01.dbf‘‘ size 100M extent management local uniform size 1m; 492 create tablespace userdata datafile ‘‘$ORACLE_HOME/oradata/userdata01.dbf‘‘ size 100M extent management local autoallocate; 493 /*在创建表空间时,设置表空间内的段空间管理模式,这里用的是自动管理*/ 494 create tablespace userdata datafile ‘‘$ORACLE_HOME/oradata/userdata01.dbf‘‘ size 100M extent management local uniform size 1m segment space management auto; 495 496 alter tablespace userdata mininum extent 10; 497 498 alter tablespace userdata default storage(initial 1m next 1m pctincrease 20); 499 500 /*undo tablespace(不能被用在字典管理模下) */ 501 create undo tablespace undo1 datafile ‘‘$ORACLE_HOME/oradata/undo101.dbf‘‘ size 40M extent management local; 502 503 show parameter undo; 504 505 /*temporary tablespace*/ 506 create temporary tablespace userdata tempfile ‘‘$ORACLE_HOME/oradata/undo101.dbf‘‘ size 10m extent management local; 507 508 /*设置数据库缺省的临时表空间*/ 509 alter database default temporary tablespace tablespace_name; 510 511 /*系统/临时/在线的undo表空间不能被offline*/ 512 alter tablespace tablespace_name offline/online; 513 514 alter tablespace tablespace_name read only; 515 516 /*重命名用户表空间*/ 517 alter tablespace tablespace_name rename datafile ‘‘$ORACLE_HOME/oradata/undo101.dbf‘‘ to ‘‘$ORACLE_HOME/oradata/undo102.dbf‘‘; 518 519 /*重命名系统表空间 ,但在重命名前必须将数据库shutdown,并重启到mount状态*/ 520 alter database rename file ‘‘$ORACLE_HOME/oradata/system01.dbf‘‘ to ‘‘$ORACLE_HOME/oradata/system02.dbf‘‘; 521 522 drop tablespace userdata including contents and datafiles;---drop tablespce 523 524 /*resize tablespace,autoextend datafile space*/ 525 alter database datafile ‘‘$ORACLE_HOME/oradata/undo102.dbf‘‘ autoextend on next 10m maxsize 500M; 526 527 /*resize datafile*/ 528 alter database datafile ‘‘$ORACLE_HOME/oradata/undo102.dbf‘‘ resize 50m; 529 530 /*给表空间扩展空间*/ 531 alter tablespace userdata add datafile ‘‘$ORACLE_HOME/oradata/undo102.dbf‘‘ size 10m; 532 533 /*将表空间设置成OMF状态*/ 534 alter system set db_create_file_dest=‘‘$ORACLE_HOME/oradata‘‘; 535 536 create tablespace userdata;---use OMF status to create tablespace; 537 538 drop tablespace userdata;---user OMF status to drop tablespace; 539 540 select * from dba_tablespace/v$tablespace/dba_data_files; 541 542 /*将表的某分区移动到另一个表空间*/ 543 alter table table_name move partition partition_name tablespace tablespace_name; 544 545 ###### ORACLE storage structure and relationships ######### 546 547 /*手工分配表空间段的分区(extend)大小*/ 548 alter table kong.test12 allocate extent(size 1m datafile ‘‘$ORACLE_HOME/oradata/undo102.dbf‘‘); 549 550 alter table kong.test12 deallocate unused; ---释放表中没有用到的分区 551 552 show parameter db; 553 554 alter system set db_8k_cache_size=10m; ---配置8k块的内存空间块参数 555 556 select * from dba_extents/dba_segments/data_tablespace; 557 558 select * from dba_free_space/dba_data_file/data_tablespace; 559 560 /*数据对象所占用的字节数*/ 561 select sum(bytes) from dba_extents where onwer=‘‘kong‘‘ and segment_name =‘‘table_name‘‘; 562 563 ############ UNDO Data ################ 564 565 show parameter undo; 566 567 alter tablespace users offline normal; 568 569 alter tablespace users offline immediate; 570 571 recover datafile ‘‘$ORACLE_HOME/oradata/undo102.dbf‘‘; 572 573 alter tablespace users online ; 574 575 select * from dba_rollback_segs; 576 577 alter system set undo_tablespace=undotbs1; 578 579 /*忽略回滚段的错误提示*/ 580 alter system set undo_suppress_errors=true; 581 582 /*在自动管理模式下,不会真正建立rbs1;在手工管理模式则可以建立,且是私有回滚段*/ 583 create rollback segment rbs1 tablespace undotbs; 584 585 desc dbms_flashback; 586 587 /*在提交了修改的数据后,9i提供了旧数据的回闪操作,将修改前的数据只读给用户看,但这部分数据不会又恢复在表中,而是旧数据的一个映射*/ 588 execute dbms_flashback.enable_at_time(‘‘26-JAN-04:12:17:00 pm‘‘); 589 590 execute dbms_flashback.disable; 591 592 /*回滚段的统计信息*/ 593 select end_time,begin_time,undoblks from v$undostat; 594 595 /*undo表空间的大小计算公式: UndoSpace=[UR * (UPS * DBS)] + (DBS * 24) 596 UR :UNDO_RETENTION 保留的时间(秒) 597 UPS :每秒的回滚数据块 598 DBS:系统EXTENT和FILE SIZE(也就是db_block_size)*/ 599 600 select * from dba_rollback_segs/v$rollname/v$rollstat/v$undostat/v$session/v$transaction; 601 602 show parameter transactions; 603 604 show parameter rollback; 605 606 /*在手工管理模式下,建立公共的回滚段*/ 607 create public rollback segment prbs1 tablespace undotbs; 608 609 alter rollback segment rbs1 online;----在手工管理模式 610 611 /*在手工管理模式中,initSID.ora中指定 undo_management=manual 、rollback_segment=(‘‘rbs1‘‘,‘‘rbs2‘‘,...)、 612 transactions=100 、transactions_per_rollback_segment=10 613 然后 shutdown immediate ,startup pfile=....\???.ora */ 614 615 ########## Managing Tables ########### 616 617 /*char type maxlen=2000;varchar2 type maxlen=4000 bytes 618 rowid 是18位的64进制字符串 (10个bytes 80 bits) 619 rowid组成: object#(对象号)--32bits,6位 620 rfile#(相对文件号)--10bits,3位 621 block#(块号)--22bits,6位 622 row#(行号)--16bits,3位 623 64进制: A-Z,a-z,0-9,/,+ 共64个符号 624 625 dbms_rowid 包中的函数可以提供对rowid的解释*/ 626 627 select rowid,dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_row_number(rowid) from table_name; 628 629 create table test2 630 ( 631 id int, 632 lname varchar2(20) not null, 633 fname varchar2(20) constraint ck_1 check(fname like ‘‘k%‘‘), 634 empdate date default sysdate) 635 ) tablespace tablespace_name; 636 637 638 create global temporary table test2 on commit delete/preserve rows as select * from kong.authors; 639 640 create table user.table(...) tablespace tablespace_name storage(...) pctfree10 pctused 40; 641 642 alter table user.tablename pctfree 20 pctused 50 storage(...);---changing table storage 643 644 /*手工分配分区,分配的数据文件必须是表所在表空间内的数据文件*/ 645 alter table user.table_name allocate extent(size 500k datafile ‘‘...‘‘); 646 647 /*释放表中没有用到的空间*/ 648 alter table table_name deallocate unused; 649 650 alter table table_name deallocate unused keep 8k; 651 652 /*将非分区表的表空间搬到新的表空间,在移动表空间后,原表中的索引对象将会不可用,必须重建*/ 653 alter table user.table_name move tablespace new_tablespace_name; 654 655 create index index_name on user.table_name(column_name) tablespace users; 656 657 alter index index_name rebuild; 658 659 drop table table_name [CASCADE CONSTRAINTS]; 660 661 alter table user.table_name drop column col_name [CASCADE CONSTRAINTS CHECKPOINT 1000];---drop column 662 663 /*给表中不用的列做标记*/ 664 alter table user.table_name set unused column comments CASCADE CONSTRAINTS; 665 666 /*drop表中不用的做了标记列*/ 667 alter table user.table_name drop unused columns checkpoint 1000; 668 669 /*当在drop col是出现异常,使用CONTINUE,防止重删前面的column*/ 670 ALTER TABLE USER.TABLE_NAME DROP COLUMNS CONTINUE CHECKPOINT 1000; 671 672 select * from dba_tables/dba_objects; 673 674 ######## managing indexes ########## 675 676 /*create index*/ 677 example: 678 /*创建一般索引*/ 679 create index index_name on table_name(column_name) tablespace tablespace_name; 680 /*创建位图索引*/ 681 create bitmap index index_name on table_name(column_name1,column_name2) tablespace tablespace_name; 682 /*索引中不能用pctused*/ 683 create [bitmap] index index_name on table_name(column_name) tablespace tablespace_name pctfree 20 storage(inital 100k next 100k) ; 684 /*大数据量的索引最好不要做日志*/ 685 create [bitmap] index index_name table_name(column_name1,column_name2) tablespace_name pctfree 20 storage(inital 100k next 100k) nologging; 686 /*创建反转索引*/ 687 create index index_name on table_name(column_name) reverse; 688 /*创建函数索引*/ 689 create index index_name on table_name(function_name(column_name)) tablespace tablespace_name; 690 /*建表时创建约束条件*/ 691 create table user.table_name(column_name number(7) constraint constraint_name primary key deferrable using index storage(initial 100k next 100k) tablespace tablespace_name,column_name2 varchar2(25) constraint constraint_name not null,column_name3 number(7)) tablespace tablespace_name; 692 693 /*给创建bitmap index分配的内存空间参数,以加速建索引*/ 694 show parameter create_bit; 695 696 /*改变索引的存储参数*/ 697 alter index index_name pctfree 30 storage(initial 200k next 200k); 698 699 /*给索引手工分配一个分区*/ 700 alter index index_name allocate extent (size 200k datafile ‘‘$ORACLE/oradata/..‘‘); 701 702 /*释放索引中没用的空间*/ 703 alter index index_name deallocate unused; 704 705 /*索引重建*/ 706 alter index index_name rebuild tablespace tablespace_name; 707 708 /*普通索引和反转索引的互换*/ 709 alter index index_name rebuild tablespace tablespace_name reverse; 710 711 /*重建索引时,不锁表*/ 712 alter index index_name rebuild online; 713 714 /*给索引整理碎片*/ 715 alter index index_name COALESCE; 716 717 /*分析索引,事实上是更新统计的过程*/ 718 analyze index index_name validate structure; 719 720 desc index_state; 721 722 drop index index_name; 723 724 alter index index_name monitoring usage;-----监视索引是否被用到 725 726 alter index index_name nomonitoring usage;----取消监视 727 728 /*有关索引信息的视图*/ 729 select * from dba_indexes/dba_ind_columns/dbs_ind_expressions/v$object_usage; 730 731 ########## 数据完整性的管理(Maintaining data integrity) ########## 732 733 alter table table_name drop constraint constraint_name;----drop 约束 734 735 alter table table_name add constraint constraint_name primary key(column_name1,column_name2);-----创建主键 736 737 alter table table_name add constraint constraint_name unique(column_name1,column_name2);---创建唯一约束 738 739 /*创建外键约束*/ 740 alter table table_name add constraint constraint_name foreign key(column_name1) references table_name(column_name1); 741 742 /*不效验老数据,只约束新的数据[enable/disable:约束/不约束新数据;novalidate/validate:不对/对老数据进行验证]*/ 743 alter table table_name add constraint constraint_name check(column_name like ‘‘B%‘‘) enable/disable novalidate/validate; 744 745 /*修改约束条件,延时验证,commit时验证*/ 746 alter table table_name modify constraint constraint_name initially deferred; 747 748 /*修改约束条件,立即验证*/ 749 alter table table_name modify constraint constraint_name initially immediate; 750 751 alter session set constraints=deferred/immediate; 752 753 /*drop一个有外键的主键表,带cascade constraints参数级联删除*/ 754 drop table table_name cascade constraints; 755 756 /*当truncate外键表时,先将外键设为无效,再truncate;*/ 757 truncate table table_name; 758 759 /*设约束条件无效*/ 760 alter table table_name disable constraint constraint_name; 761 762 alter table table_name enable novalidate constraint constraint_name; 763 764 /*将无效约束的数据行放入exception的表中,此表记录了违反数据约束的行的行号;在此之前,要先建exceptions表*/ 765 alter table table_name add constraint constraint_name check(column_name >15) enable validate exceptions into exceptions; 766 767 /*运行创建exceptions表的脚本*/ 768 start $ORACLE_HOME/rdbms/admin/utlexcpt.sql; 769 770 /*获取约束条件信息的表或视图*/ 771 select * from user_constraints/dba_constraints/dba_cons_columns; 772 773 ################## managing password security and resources #################### 774 775 alter user user_name account unlock/open;----锁定/打开用户; 776 777 alter user user_name password expire;---设定口令到期 778 779 /*建立口令配置文件,failed_login_attempts口令输多少次后锁,password_lock_times指多少天后口令被自动解锁*/ 780 create profile profile_name limit failed_login_attempts 3 password_lock_times 1/1440; 781 /*创建口令配置文件*/ 782 create profile profile_name limit failed_login_attempts 3 password_lock_time unlimited password_life_time 30 password_reuse_time 30 password_verify_function verify_function password_grace_time 5; 783 /*建立资源配置文件*/ 784 create profile prfile_name limit session_per_user 2 cpu_per_session 10000 idle_time 60 connect_time 480; 785 786 alter user user_name profile profile_name; 787 788 /*设置口令解锁时间*/ 789 alter profile profile_name limit password_lock_time 1/24; 790 791 /*password_life_time指口令文件多少时间到期,password_grace_time指在第一次成功登录后到口令到期有多少天时间可改变口令*/ 792 alter profile profile_name limit password_lift_time 2 password_grace_time 3; 793 794 /*password_reuse_time指口令在多少天内可被重用,password_reuse_max口令可被重用的最大次数*/ 795 alter profile profile_name limit password_reuse_time 10[password_reuse_max 3]; 796 797 alter user user_name identified by input_password;-----修改用户口令 798 799 drop profile profile_name; 800 801 /*建立了profile后,且指定给某个用户,则必须用CASCADE才能删除*/ 802 drop profile profile_name CASCADE; 803 804 alter system set resource_limit=true;---启用自愿限制,缺省是false 805 806 /*配置资源参数*/ 807 alter profile profile_name limit cpu_per_session 10000 connect_time 60 idle_time 5; 808 /*资源参数(session级) 809 cpu_per_session 每个session占用cpu的时间 单位1/100秒 810 sessions_per_user 允许每个用户的并行session数 811 connect_time 允许连接的时间 单位分钟 812 idle_time 连接被空闲多少时间后,被自动断开 单位分钟 813 logical_reads_per_session 读块数 814 ***_sga 用户能够在SGA中使用的私有的空间数 单位bytes 815 816 (call级) 817 cpu_per_call 每次(1/100秒)调用cpu的时间 818 logical_reads_per_call 每次调用能够读的块数 819 */ 820 821 alter profile profile_name limit cpu_per_call 1000 logical_reads_per_call 10; 822 823 desc dbms_resouce_manager;---资源管理器包 824 825 /*获取资源信息的表或视图*/ 826 select * from dba_users/dba_profiles; 827 828 ###### Managing users ############ 829 830 show parameter os; 831 832 create user testuser1 identified by kxf_001; 833 834 grant connect,createtable to testuser1; 835 836 alter user testuser1 quota 10m on tablespace_name; 837 838 /*创建用户*/ 839 create user user_name identified by password default tablespace tablespace_name temporary tablespace tablespace_name quota 15m on tablespace_name password expire; 840 841 /*数据库级设定缺省临时表空间*/ 842 alter database default temporary tablespace tablespace_name; 843 844 /*制定数据库级的缺省表空间*/ 845 alter database default tablespace tablespace_name; 846 847 /*创建os级审核的用户,需知道os_authent_prefix,表示oracle和os口令对应的前缀,‘‘OPS$‘‘为此参数的值,此值可以任意设置*/ 848 create user user_name identified by externally default OPS$tablespace_name tablespace_name temporary tablespace tablespace_name quota 15m on tablespace_name password expire; 849 850 /*修改用户使用表空间的限额,回滚表空间和临时表空间不允许授予限额*/ 851 alter user user_name quota 5m on tablespace_name; 852 853 /*删除用户或删除级联用户(用户对象下有对象的要用CASCADE,将其下一些对象一起删除)*/ 854 drop user user_name [CASCADE]; 855 856 /*每个用户在哪些表空间下有些什么限额*/ 857 desc dba_ts_quotas;select * from dba_ts_quotas where username=‘‘...‘‘; 858 859 /*改变用户的缺省表空间*/ 860 alter user user_name default tablespace tablespace_name; 861 862 ######### Managing Privileges ############# 863 864 grant create table,create session to user_name; 865 866 grant create any table to user_name; revoke create any table from user_name; 867 868 /*授予权限语法,public 标识所有用户,with admin option允许能将权限授予第三者的权限*/ 869 grant system_privs,[......] to [user/role/public],[....] [with admin option]; 870 871 select * from v$pwfile_users; 872 873 /*当 O7_dictionary_accessiblity参数为True时,标识select any table时,包括系统表也能select ,否则,不包含系统表;缺省为false*/ 874 show parameter O7; 875 876 /*由于 O7_dictionary_accessiblity为静态参数,不能动态改变,故加scope=spfile,下次启动时才生效*/ 877 alter system set O7_dictionary_accessiblity=true scope=spfile; 878 879 /*授予对象中的某些字段的权限,如select 某表中的某些字段的权限*/ 880 grant [object_privs(column,....)],[...] on object_name to user/role/public,... with grant option; 881 882 /*oracle不允许授予select某列的权限,但可以授insert ,update某列的权限*/ 883 grant insert(column_name1,column_name2,...) on table_name to user_name with grant option; 884 885 select * from dba_sys_privs/session_privs/dba_tab_privs/user_tab_privs/dba_col_privs/user_col_privs; 886 887 /*db/os/none 审计被记录在 数据库/操作系统/不审计 缺省是none*/ 888 show parameter audit_trail; 889 890 /*启动对表的select动作*/ 891 audit select on user.table_name by session; 892 893 /*by session在每个session中发出command只记录一次,by access则每个command都记录*/ 894 audit [create table][select/update/insert on object by session/access][whenever successful/not successful]; 895 896 desc dbms_fga;---进一步设计,则可使用dbms_fgs包 897 898 /*取消审计*/ 899 noaudit select on user.table_name; 900 901 /*查被审计信息*/ 902 select * from all_def_audit_opts/dba_stmt_audit_opts/dba_priv_audit_opts/dba_obj_audit_opts; 903 904 /*获取审计记录*/ 905 select * from dba_audit_trail/dba_audit_exists/dba_audit_object/dba_audit_session/dba_audit_statement; 906 907 ########### Managing Role ################# 908 909 create role role_name; grant select on table_name to role_name; grant role_name to user_name; set role role_name; 910 911 create role role_name; 912 create role role_name identified by password; 913 create role role_name identified externally; 914 915 set role role_name ; ----激活role 916 set role role_name identified by password; 917 918 alter role role_name not identified; 919 alter role role_name identified by password; 920 alter role role_name identified externally; 921 922 grant priv_name to role_name [WITH ADMIN OPTION]; 923 grant update(column_name1,col_name2,...) on table_name to role_name; 924 grant role_name1 to role_name2; 925 926 /*建立default role,用户登录时,缺省激活default role*/ 927 alter user user_name default role role_name1,role_name2,...; 928 alter user user_name default role all; 929 alter user user_name default role all except role_name1,...; 930 alter user user_name default role none; 931 932 set role role1 [identified by password],role2,....; 933 set role all; 934 set role except role1,role2,...; 935 set role none; 936 937 revoke role_name from user_name; 938 revoke role_name from public; 939 940 drop role role_name; 941 942 select * from dba_roles/dba_role_privs/role_role_privs/dba_sys_privs/role_sys_privs/role_tab_privs/session_roles; 943 944 ########### Basic SQL SELECT ################ 945 946 select col_name as col_alias from table_name ; 947 948 select col_name from table_name where col1 like ‘‘_o%‘‘; ----‘‘_‘‘匹配单个字符 949 950 /*使用字符函数(右边截取,字段中包含某个字符,左边填充某字符到固定位数,右边填充某字符到固定位数)*/ 951 select substr(col1,-3,5),instr(col2,‘‘g‘‘),LPAD(col3,10,‘‘$‘‘),RPAD(col4,10,‘‘%‘‘) from table_name; 952 953 /*使用数字函数(往右/左几位四舍五入,取整,取余)*/ 954 select round(col1,-2),trunc(col2),mod(col3) from table_name ; 955 956 /*使用日期函数(计算两个日期间相差几个星期,两个日期间相隔几个月,在某个月份上加几个月,某个日期的下一个日期, 957 某日期所在月的最后的日期,对某个日期的月分四舍五入,对某个日期的月份进行取整)*/ 958 select (sysdate-col1)/7 week,months_between(sysdate,col1),add_months(col1,2),next_day(sysdate,‘‘FRIDAY‘‘),last_day(sysdate), 959 round(sysdate,‘‘MONTH‘‘),trunc(sysdate,‘‘MONTH‘‘) from table_name; 960 961 /*使用NULL函数(当expr1为空取expr2/当expr1为空取expr2,否则取expr3/当expr1=expr2返回空)*/ 962 select nvl(expr1,expr2),nvl2(expr1,expr2,expr3),nullif(expr1,expr2) from table_name; 963 964 select column1,column2,column3, case column2 when ‘‘50‘‘ then column2*1.1 965 when ‘‘30‘‘ then column2*2.1 966 when ‘‘10‘‘ then column3/20 967 else column3 968 end as ttt 969 from table_name ; ------使用case函数 970 971 select table1.col1,table2.col2 from table1 972 [CROSS JOIN table2] | -----笛卡儿连接 973 [NATURAL JOIN table2] | -----用两个表中的同名列连接 974 [JOIN table2 USING (column_name)] | -----用两个表中的同名列中的某一列或几列连接 975 [JOIN table2 976 ON (table1.col1=table2.col2)] | 977 [LEFT|RIGHT|FULL OUTER JOIN table2 ------相当于(+)=,=(+)连接,全外连接 978 ON (table1.col1=table2.col2)]; ------SQL 1999中的JOIN语法; 979 980 example: 981 select col1,col2 from table1 t1 982 join table2 t2 983 on t1.col1=t2.col2 and t1.col3=t2.col1 984 join table3 t3 985 on t2.col1=t3.col3; 986 987 select * from table_name where col1 < any (select col2 from table_name2 where continue group by col3); 988 989 select * from table_name where col1 < all (select col2 from table_name2 where continue group by col3); 990 991 insert into (select col1,col2,col3 form table_name where col1> 50 with check option) values (value1,value2,value3); 992 993 MERGE INTO table_name table1 994 USING table_name2 table2 995 ON (table1.col1=table2.col2) 996 WHEN MATCHED THEN 997 UPDATE SET 998 table1.col1=table2.col2, 999 table1.col2=table2.col3, 1000 ... 1001 WHEN NOT MATCHED THEN 1002 INSERT VALUES(table2.col1,table2.col2,table2.col3,...); -----合并语句 1003 1004 ##################### CREATE/ALTER TABLE ####################### 1005 1006 alter table table_name drop column column_name ;---drop column 1007 1008 alter table table_name set unused (col1,col2,...);----设置列无效,这个比较快。 1009 alter table table_name drop unused columns;---删除被设为无效的列 1010 1011 rename table_name1 to table_name2; ---重命名表 1012 1013 comment on table table_name is ‘‘comment message‘‘;----给表放入注释信息 1014 1015 create table table_name 1016 (col1 int not null,col2 varchar2(20),col3 varchar2(20), 1017 constraint uk_test2_1 unique(col2,col3))); -----定义表中的约束条件 1018 1019 alter table table_name add constraint pk_test2 primary key(col1,col2,...); ----创建主键 1020 1021 /*建立外键*/ 1022 create table table_name (rid int,name varchar2(20),constraint fk_test3 foreign key(rid) references other_table_name(id)); 1023 1024 alter table table_name add constraint ck_test3 check(name like ‘‘K%‘‘); 1025 1026 alter table table_name drop constraint constraint_name; 1027 1028 alter table table_name drop primary key cascade;----级联删除主键 1029 1030 alter table table_name disable/enable constraint constraint_name;----使约束暂时无效 1031 1032 /*删除列,并级联删除此列下的约束条件*/ 1033 alter table table_name drop column column_name cascade constraint; 1034 1035 select * from user_constraints/user_cons_columns;---约束条件相关视图 1036 1037 ############## Create Views ##################### 1038 1039 CREATE [OR REPLACE] [FORCE|NOFORCE] VIEW view_name [(alias[,alias]...)] 1040 AS subquery 1041 [WITH CHECK OPTION [CONSTRAINT constraint_name]] 1042 [WITH READ ONLY [CONSTRAINT constraint_name]]; ------创建视图的语法 1043 1044 example: Create or replace view testview as select col1,col2,col3 from table_name; ------创建视图 1045 /*使用别名*/ 1046 Create or replace view testview as select col1,sum(col2) col2_alias from table_name; 1047 /*创建复杂视图*/ 1048 Create view view_name (alias1,alias2,alias3,alias4) as select d.col1,min(e.col1),max(e.col1),***g(e.col1) from table_name1 e,table_name2 d where e.col2=d.col2 group by d.col1; 1049 /*当用update修改数据时,必须满足视图的col1>10的条件,不满足则不能被改变.*/ 1050 Create or replace view view_name as select * from table_name where col1>10 with check option; 1051 1052 /*改变视图的值.对于简单视图可以用update语法修改表数据,但复杂视图则不一定能改。如使用了函数,group by ,distinct等的列*/ 1053 update view_name set col1=value1; 1054 1055 /*TOP-N分析*/ 1056 select [column_list],rownum from (select [column_list] from table_name order by Top-N_column) where rownum<=N; 1057 1058 /*找出某列三条最大值的记录*/ 1059 example: select rownum as rank ,col1 ,col2 from (select col1 ,col2 from table_name order by col2 desc) where rownum<=3; 1060 1061 ############# Other database Object ############### 1062 1063 CREATE SEQUENCE sequence_name [INCREMENT BY n] 1064 [START WITH n] 1065 [{MAXVALUE n | NOMAXVALUE}] 1066 [{MINVALUE n | NOMINVALUE}] 1067 [{CYCEL | NOCYCLE}] 1068 [{CACHE n | NOCACHE}]; -----创建SEQUENCE 1069 1070 example: 1071 CREATE SEQUENCE sequence_name INCREMENT BY 10 1072 START WITH 120 1073 MAXVALUE 9999 1074 NOCACHE 1075 NOCYCLE; 1076 1077 select * from user_sequences ;---当前用户下记录sequence的视图 1078 1079 select sequence_name.nextval,sequence_name.currval from dual;-----sequence的引用 1080 1081 alter sequence sequence_name INCREMENT BY 20 1082 MAXVALUE 999999 1083 NOCACHE 1084 NOCYCLE; -----修改sequence,不能改变起始序号 1085 1086 drop sequence sequence_name; ----删除sequence 1087 1088 CREATE [PUBLIC] SYNONYM synonym_name FOR object; ------创建同义词 1089 1090 DROP [PUBLIC] SYNONYM synonym_name;----删除同义词 1091 1092 CREATE PUBLIC DATABASE LINK link_name USEING OBJECT;----创建DBLINK 1093 1094 select * from [email protected]_name; ----访问远程数据库中的对象 1095 1096 /*union 操作,它将两个集合的交集部分压缩,并对数据排序*/ 1097 select col1,col2,col3 from table1_name union select col1,col2,col3 from table2_name; 1098 1099 /*union all 操作,两个集合的交集部分不压缩,且不对数据排序*/ 1100 select col1,col2,col3 from table1_name union all select col1,col2,col3 from table2_name; 1101 1102 /*intersect 操作,求两个集合的交集,它将对重复数据进行压缩,且排序*/ 1103 select col1,col2,col3 from table1_name intersect select col1,col2,col3 from table2_name; 1104 1105 /*minus 操作,集合减,它将压缩两个集合减后的重复记录, 且对数据排序*/ 1106 select col1,col2,col3 from table1_name minus select col1,col2,col3 from table2_name; 1107 1108 /*EXTRACT 抽取时间函数. 此例是抽取当前日期中的年*/ 1109 select EXTRACT(YEAR FROM SYSDATE) from dual; 1110 /*EXTRACT 抽取时间函数. 此例是抽取当前日期中的月*/ 1111 select EXTRACT(MONTH FROM SYSDATE) from dual; 1112 1113 ########################## 增强的 group by 子句 ######################### 1114 1115 select [column,] group_function(column)... 1116 from table 1117 [WHERE condition] 1118 [GROUP BY [ROLLUP] group_by_expression] 1119 [H***ING h***ing_expression]; 1120 [ORDER BY column]; -------ROLLUP操作字,对group by子句的各字段从右到左进行再聚合 1121 1122 example: 1123 /*其结果看起来象对col1做小计*/ 1124 select col1,col2,sum(col3) from table group by rollup(col1,col2); 1125 /*复合rollup表达式*/ 1126 select col1,col2,sum(col3) from table group by rollup((col1,col2)); 1127 1128 select [column,] group_function(column)... 1129 from table 1130 [WHERE condition] 1131 [GROUP BY [CUBE] group_by_expression] 1132 [H***ING h***ing_expression]; 1133 [ORDER BY column]; -------CUBE操作字,除完成ROLLUP的功能外,再对ROLLUP后的结果集从右到左再聚合 1134 1135 example: 1136 /*其结果看起来象对col1做小计后,再对col2做小计,最后算总计*/ 1137 select col1,col2,sum(col3) from table group by cube(col1,col2); 1138 /*复合rollup表达式*/ 1139 select col1,col2,sum(col3) from table group by cube((col1,col2)); 1140 /*混合rollup,cube表达式*/ 1141 select col1,col2,col3,sum(col4) from table group by col1,rollup(col2),cube(col3); 1142 1143 /*GROUPING(expr)函数,查看select语句种以何字段聚合,其取值为0或1*/ 1144 select [column,] group_function(column)...,GROUPING(expr) 1145 from table 1146 [WHERE condition] 1147 [GROUP BY [ROLLUP] group_by_expression] 1148 [H***ING h***ing_expression]; 1149 [ORDER BY column]; 1150 1151 example: 1152 select col1,col2,sum(col3),grouping(col1),grouping(col2) from table group by cube(col1,col2); 1153 1154 /*grouping sets操作,对group by结果集先对col1求和,再对col2求和,最后将其结果集并在一起*/ 1155 select col1,col2,sum(col3) from table group by grouping sets((col1),(col2)); 1156 1157
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