Oracle查询优化-插入更新与删除

Posted 2020-08-20 舒山

--插入、更新与删除
--1.插入新纪录
--1.1.建立测试表
DROP TABLE TEST;
CREATE TABLE TEST(
C1 VARCHAR2(10) DEFAULT ‘默认1‘,
C2 VARCHAR2(10) DEFAULT ‘默认2‘,
C3 VARCHAR2(10) DEFAULT ‘默认3‘,
C4 DATE DEFAULT SYSDATE
);
--1.2.增加数据
INSERT INTO TEST(C1,C2,C3) VALUES(DEFAULT,NULL,‘手输值‘);
--1.3.查询
SELECT * FROM TEST;
--1.4.总结
/**
 *1.如果INSERT INTO 语句中没有包含有默认值的列，如C4，则会插入默认值；
 *2.如果有包含默认值的列，则应该用DEFAULT关键字才能添加默认值，如C1；
 *3.如果已显示设定了NULL或其他值，则不会产生默认值，如C2和C3。
 */
--2.复制表及数据
CREATE TABLE TEST2 AS SELECT * FROM TEST;
--或者先复制表结构，然后再插入数据
CREATE TABLE TEST2 AS SELECT * FROM TEST WHERE 1=2;
/*复制的表不包含默认值等约束条件，使用这种方式复制表后，需要重建默认值及索引和约束等信息*/
--3.用WITH CHECK OPTION限制数据录入
INSERT INTO (SELECT EMPNO,ENAME,HIREDATE FROM EMP
WHERE HIREDATE <= SYSDATE WITH CHECK OPTION)VALUES (9999,‘TEST‘,SYSDATE+1)
 
ORA-01402: view WITH CHECK OPTION where-clause violation--视图WITH CHECK OPTION的where子句违规
--4.多表插入语句
--建立测试表
DROP TABLE EMP1;
DROP TABLE EMP2;
CREATE TABLE EMP1 AS SELECT EMPNO,ENAME,JOB FROM EMP WHERE 1=2;
CREATE TABLE EMP2 AS SELECT EMPNO,ENAME,DEPTNO FROM EMP WHERE 1=2;
--4.1.无条件INSERT ALL
INSERT ALL
       INTO EMP1(EMPNO,ENAME,JOB) VALUES (EMPNO,ENAME,JOB)
       INTO EMP2(EMPNO,ENAME,DEPTNO) VALUES (EMPNO,ENAME,DEPTNO)
SELECT EMPNO,ENAME,JOB,DEPTNO FROM EMP WHERE DEPTNO IN (10,20);
SELECT * FROM EMP1;
EMPNO ENAME      JOB
----- ---------- ---------
 7369 SMITH      CLERK
 7566 JONES      MANAGER
 7782 CLARK      MANAGER
 7788 SCOTT      ANALYST
 7839 KING       PRESIDENT
 7876 ADAMS      CLERK
 7902 FORD       ANALYST
 7934 MILLER     CLERK
SELECT * FROM EMP2;
EMPNO ENAME      DEPTNO
----- ---------- ------
 7369 SMITH          20
 7566 JONES          20
 7782 CLARK          10
 7788 SCOTT          20
 7839 KING           10
 7876 ADAMS          20
 7902 FORD           20
 7934 MILLER         10
--4.2.有条件INSERT ALL
DELETE EMP1;
DELETE EMP2;
INSERT ALL
       WHEN JOB IN (‘SALESMAN‘,‘MANAGER‘) THEN
       INTO EMP1(EMPNO,ENAME,JOB)VALUES(EMPNO,ENAME,JOB)
       WHEN DEPTNO IN(‘20‘,‘30‘)THEN
       INTO EMP2(EMPNO,ENAME,DEPTNO)VALUES(EMPNO,ENAME,DEPTNO)
SELECT EMPNO,ENAME,JOB,DEPTNO FROM EMP;
SELECT * FROM EMP1;
EMPNO ENAME      JOB
----- ---------- ---------
 7499 ALLEN      SALESMAN
 7521 WARD       SALESMAN
 7566 JONES      MANAGER
 7654 MARTIN     SALESMAN
 7698 BLAKE      MANAGER
 7782 CLARK      MANAGER
 7844 TURNER     SALESMAN
SELECT * FROM EMP2;
EMPNO ENAME      DEPTNO
----- ---------- ------
 7369 SMITH          20
 7499 ALLEN          30
 7521 WARD           30
 7566 JONES          20
 7654 MARTIN         30
 7698 BLAKE          30
 7788 SCOTT          20
 7844 TURNER         30
 7876 ADAMS          20
 7900 JAMES          30
 7902 FORD           20
--4.3.有条件INSERT FIRST
DELETE EMP1;
DELETE EMP2;
INSERT FIRST
       WHEN JOB IN (‘SALESMAN‘,‘MANAGER‘) THEN
       INTO EMP1(EMPNO,ENAME,JOB)VALUES(EMPNO,ENAME,JOB)
       WHEN DEPTNO IN(‘20‘,‘30‘) THEN
       INTO EMP2(EMPNO,ENAME,DEPTNO) VALUES(EMPNO,ENAME,DEPTNO)
SELECT EMPNO,ENAME,JOB,DEPTNO FROM EMP;
SELECT * FROM EMP1;
EMPNO ENAME      JOB
----- ---------- ---------
 7499 ALLEN      SALESMAN
 7521 WARD       SALESMAN
 7566 JONES      MANAGER
 7654 MARTIN     SALESMAN
 7698 BLAKE      MANAGER
 7782 CLARK      MANAGER
 7844 TURNER     SALESMAN
SELECT * FROM EMP2;  
EMPNO ENAME      DEPTNO
----- ---------- ------
 7369 SMITH          20
 7788 SCOTT          20
 7876 ADAMS          20
 7900 JAMES          30
 7902 FORD           20
 /*INSERT ALL与INSERT FIRST不同的是：当第一个表符合条件后，第二个表将不再插入对应的行，表二中不再有与表一相同的数据EMPNO=7654*/    
--4.4.转置INSERT
DROP TABLE T1;
DROP TABLE T2;
CREATE TABLE T2(D VARCHAR2(10),DES VARCHAR2(50));
CREATE TABLE T1 AS
SELECT ‘陇西行四首·其二‘ AS D1,
       ‘誓扫匈奴不顾身‘ AS D2,
       ‘五千貂锦丧胡尘‘ AS D3,
       ‘可怜无定河边骨‘ AS D4,
       ‘犹是春闺梦里人‘ AS D5
FROM DUAL;
/*转置 INSERT ALL*/
INSERT ALL
       INTO T2(D,DES) VALUES (‘诗名‘,D1)
       INTO T2(D,DES) VALUES (‘第一句‘,D2)
       INTO T2(D,DES) VALUES (‘第二句‘,D3)
       INTO T2(D,DES) VALUES (‘第三句‘,D4)
       INTO T2(D,DES) VALUES (‘第四句‘,D5)
SELECT D1,D2,D3,D4,D5 FROM T1;
SELECT * FROM T1; 
D1                      D2                    D3                    D4                    D5
----------------------- --------------------- --------------------- --------------------- ---------------------
陇西行四首·其二         誓扫匈奴不顾身        五千貂锦丧胡尘        可怜无定河边骨        犹是春闺梦里人
SELECT * FROM T2;
D          DES
---------- --------------------------------------------------
诗名       陇西行四首·其二
第一句     誓扫匈奴不顾身
第二句     五千貂锦丧胡尘
第三句     可怜无定河边骨
第四句     犹是春闺梦里人