oracle中插入多行数据技巧--集合应用--TRUNCATE，delete区别

CREATE TABLE EMPINFO(

EMP_ID VARCHAR(10) PRIMARY KEY,

NAME VARCHAR(6),

BIRTHDAY DATE,

SAL NUMBER(4)

);

CREATE TABLE INTEG(

INTEGER_ID VARCHAR(10) PRIMARY KEY,

HABITUDE VARCHAR(10),

SCORE NUMBER(4)

);

--建一张关系表 m-m

CREATE TABLE thing(

EMP_ID CHAR(10),

INTEGER_ID CHAR(10)

);

--alter SESSION SET NLS_DATE_FORMAT="YYYY-MM--DD";

--INSERT INTO EMPINFO VALUES('LEX_001','张三',2001-2-2,600);

INSERT INTO EMPINFO VALUES('LEX_001','张四',TO_DATE('2001-2-3','YYYY-MM-DD'),700);

INSERT INTO EMPINFO VALUES('LEX_002','张四',TO_DATE('2001-2-3','YYYY-MM-DD'),700);

INSERT INTO EMPINFO VALUES('LEX_003','张五',TO_DATE('2001-2-4','YYYY-MM-DD'),800);

INSERT INTO EMPINFO VALUES('LEX_004','张六',TO_DATE('2001-2-5','YYYY-MM-DD'),900);

INSERT INTO EMPINFO VALUES('LEX_005','张七',TO_DATE('2001-2-6','YYYY-MM-DD'),1000);

INSERT INTO EMPINFO VALUES('LEX_006','张八',TO_DATE('2001-2-7','YYYY-MM-DD'),1100);

INSERT INTO EMPINFO VALUES('LEX_007','张九',TO_DATE('2001-2-8','YYYY-MM-DD'),1200);

SELECT * FROM EMPINFO;

INSERT INTO INTEG VALUES('I_001','公司类别',4);

INSERT INTO INTEG VALUES('I_002','学习类别',2.5);

INSERT INTO INTEG VALUES('I_003','协作类别',2.5);

INSERT INTO INTEG VALUES('I_004','其他类别',1);

INSERT INTO thing VALUES('IEX_0001','I_001');

INSERT INTO thing VALUES('IEX_0002','I_002');

INSERT INTO thing VALUES('IEX_0003','I_003');

INSERT INTO thing VALUES('IEX_0004','I_004');

--第二次：

SELECT E.EMP_ID,E.NAME,E.BIRTHDAY,E.SAL

FROM EMPINFO E

WHERE E.SAL >= all (--SOME相等用some -->= <=等用some

SELECT EMP.SAL FROM EMPINFO EMP

--

where EMP.EMP_ID = E.EMP_ID

);

SELECT E.EMP_ID,E.NAME,E.BIRTHDAY,E.SAL

FROM EMPINFO E

GROUP BY E.EMP_ID,E.NAME,E.BIRTHDAY,E.SAL

SELECT E.SAL,COUNT(*)

FROM EMPINFO E

GROUP BY E.SAL

HAVING COUNT(*)>1;

--SAL为700的有两个

SELECT * FROM EMPINFO;

SELECT E.SAL--,COUNT(*)

FROM EMPINFO E

GROUP BY E.SAL

--HAVING COUNT(*)>0

ORDER BY e.SAL DESC;--ORDER BY SAL也可以多列排序 当有两条记录相同

select E.EMP_ID as 用户ID FROM EMPINFO E

UNION ALL --UNION ALL加上all去掉重复记录，并且字段必须相同

SELECT T.EMP_ID FROM THING T;-- 用户ID不能放在这里，不能改变名字

select E.EMP_ID as 用户ID FROM EMPINFO E

Intersect --交集

SELECT T.EMP_ID FROM THING T;

select E.EMP_ID as 用户ID FROM EMPINFO E

MINUS --差集

SELECT T.EMP_ID FROM THING T;

--由于thing表没有score项

--error

UPDATE SET SAL = SAL*(SELECT SCORE FROM thing

WHERE INTEG_ID = 'I_003');

SELECT * FROM THING

where EMP_ID=''

ALTER TABLE THING ADD SCORE NUMBER(5);

--INSERT INTO THING(,,S想在已经存在的表中插入单行的score分数

SELECT * FROM THING

DELETE FROM B;

TRUNCATE TABLE B;--非常危险的删除项

--插入多行

insert INTO EMPINFO (EMP_ID,NAME,BIRTHDAY,SAL )

SELECT 'LEX_005','张七',TO_DATE('2001-2-6','YYYY-MM-DD'),1000 from dual

union

SELECT 'LEX_006','张八',TO_DATE('2001-2-7','YYYY-MM-DD'),1100 from dual

union

SELECT 'LEX_007','张九',TO_DATE('2001-2-8','YYYY-MM-DD'),1200 from dual

select * from EMPINFO ;