SQL_字符操作函数
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原创作品。出自 “深蓝的blog” 博客。欢迎转载，转载时请务必注明下面出处，否则追究版权法律责任。
深蓝的blog：http://blog.csdn.net/huangyanlong/article/details/40213181
思维导图：
用简单的样例演示，例如以下列举。用最简单的操作体会字符操作函数的使用方法：
concat函数
SQL> select ename,job,concat(ename,job) from emp; ENAME JOB CONCAT(ENAME,JOB) ---------- --------- ------------------- SMITH CLERK SMITHCLERK ALLEN DBA ALLENDBA WARD DBA WARDDBA JONES MANAGER JONESMANAGER MARTIN DBA MARTINDBA BLAKE DBA BLAKEDBA CLARK MANAGER CLARKMANAGER SCOTT ANALYST SCOTTANALYST KING PRESIDENT KINGPRESIDENT TURNER DBA TURNERDBA ADAMS CLERK ADAMSCLERK JAMES DBA JAMESDBA FORD ANALYST FORDANALYST MILLER CLERK MILLERCLERK 14 rows selected
SQL> select ename,job,concat(ename,'s job is ' || job) from emp; ENAME JOB CONCAT(ENAME,'SJOBIS'||JOB) ---------- --------- ---------------------------- SMITH CLERK SMITHs job is CLERK ALLEN DBA ALLENs job is DBA WARD DBA WARDs job is DBA JONES MANAGER JONESs job is MANAGER MARTIN DBA MARTINs job is DBA BLAKE DBA BLAKEs job is DBA CLARK MANAGER CLARKs job is MANAGER SCOTT ANALYST SCOTTs job is ANALYST KING PRESIDENT KINGs job is PRESIDENT TURNER DBA TURNERs job is DBA ADAMS CLERK ADAMSs job is CLERK JAMES DBA JAMESs job is DBA FORD ANALYST FORDs job is ANALYST MILLER CLERK MILLERs job is CLERK 14 rows selected
substr函数
SQL> select ename,concat(ename,job),length(ename),instr(ename,'a') from emp where substr(job,1,5)='ANALY'; ENAME CONCAT(ENAME,JOB) LENGTH(ENAME) INSTR(ENAME,'A') ---------- ------------------- ------------- ---------------- SCOTT SCOTTANALYST 5 0 FORD FORDANALYST 4 0
length函数
SQL> select ename,length(ename) from emp; ENAME LENGTH(ENAME) ---------- ------------- SMITH 5 ALLEN 5 WARD 4 JONES 5 MARTIN 6 BLAKE 5 CLARK 5 SCOTT 5 KING 4 TURNER 6 ADAMS 5 JAMES 5 FORD 4 MILLER 6 14 rows selected
instr函数
SQL> select ename,instr(ename,'A') from emp ; ENAME INSTR(ENAME,'A') ---------- ---------------- SMITH 0 ALLEN 1 WARD 2 JONES 0 MARTIN 2 BLAKE 3 CLARK 3 SCOTT 0 KING 0 TURNER 0 ADAMS 1 JAMES 2 FORD 0 MILLER 0 14 rows selected
SQL> select ename,concat(ename,job),length(ename),instr(ename,'a') from emp; ENAME CONCAT(ENAME,JOB) LENGTH(ENAME) INSTR(ENAME,'A') ---------- ------------------- ------------- ---------------- SMITH SMITHCLERK 5 0 ALLEN ALLENDBA 5 0 WARD WARDDBA 4 0 JONES JONESMANAGER 5 0 MARTIN MARTINDBA 6 0 BLAKE BLAKEDBA 5 0 CLARK CLARKMANAGER 5 0 SCOTT SCOTTANALYST 5 0 KING KINGPRESIDENT 4 0 TURNER TURNERDBA 6 0 ADAMS ADAMSCLERK 5 0 JAMES JAMESDBA 5 0 FORD FORDANALYST 4 0 MILLER MILLERCLERK 6 0 14 rows selected
lpad函数
SQL> select ename,lpad(ename,10,'-') from emp; ENAME LPAD(ENAME,10,'-') ---------- -------------------- SMITH -----SMITH ALLEN -----ALLEN WARD ------WARD JONES -----JONES MARTIN ----MARTIN BLAKE -----BLAKE CLARK -----CLARK SCOTT -----SCOTT KING ------KING TURNER ----TURNER ADAMS -----ADAMS JAMES -----JAMES FORD ------FORD MILLER ----MILLER 14 rows selected
trim函数
SQL> select trim('s' from 'sdfde') from dual;
TRIM('S'FROM'SDFDE')
--------------------
dfde
SQL> select trim('s' from 'sdsfsde') from dual;
TRIM('S'FROM'SDSFSDE')
----------------------
dsfsde
SQL> select trim('s' from 'ssdsfsde') from dual;
TRIM('S'FROM'SSDSFSDE')
-----------------------
dsfsde
原创作品。出自 “深蓝的blog” 博客。欢迎转载，转载时请务必注明下面出处，否则追究版权法律责任。
深蓝的blog：http://blog.csdn.net/huangyanlong/article/details/40213181
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