基本的 SQL 语句

SELECT

select

SQLSQL*PLUS

selectSelection Projection Table 1Table 2Table 1Table 1Join

selectselectfrom DISTINCT column|expressionalias SELECT *|{[DISTINCT] column|expression [alias],...}FROM table;

fromMultiply *Divide /Subtract -Add +DescriptionOperator

SELECT EMPNO, SAL, SAL + 300FROM EMP;SAL+300 EMP

SELECT EMPNO, SAL, 12*SAL+100FROM EMP;SELECT EMPNO, SAL, 12*(SAL+100)FROM EMP;

"NOT NULLPRIMARY KEY)

SELECT ENAME AS , JOB FROM EMP;

||SELECTENAME||EMPNO AS "Employees"FROM EMP;SELECT ENAME ||' is a '||EMPNO AS "Employee Details"FROM EMP;

SELECT DEPTNOFROM emp;SELECT DISTINCT DEPTNOFROM emp;

SQLPLUS DESCRIBE emp

WHEREWHEREFROM

SELECT *|{[DISTINCT] column|expression [alias],...}FROM table;

DD-MON-RRSELECT EMPNO, ENAME, JOB, DEPTNOFROM empWHERE DEPTNO = 90 ;SELECT EMPNO, ENAME, JOB, DEPTNOFROM empWHERE ENAME = KING ;

Not equal to

Between two values (inclusive)BETWEEN ...AND...Match any of a list of values IN(set)Match a character pattern LIKEIs a null value IS NULLLess than

Equal to=MeaningOperator

select empno, ename, job, sal, deptno from emp where sal < 2000;

select empno, ename, job, sal, deptno from emp where sal between 1000 and 2000;

select empno, ename, job, sal, deptno from emp where deptno in (20,30);

select empno, ename, job, sal, deptno from emp where ename like 'K%';%_

select empno, ename, job, comm, deptno from emp where comm is NULL;

Returns TRUE if the condition is falseNOTReturns TRUE if either component condition is trueORReturns TRUE if both component conditions are trueANDMeaningOperatorselect empno, ename, job, sal, deptno from emp where sal < 3000 and ename like 'J%';

select empno, ename, job, sal, deptno from emp where sal < 3000 and ename not like 'J%';

select empno, ename, job, sal, deptno from emp where sal < 3000 or ename like K%';

select empno, ename, job, sal, deptno from emp where sal < 3000 and ename not in ('WARD','KING');

1234IS [NOT] NULL LIKE [NOT] IN5[NOT] BETWEEN6NOT7AND8OR

select empno, ename, job, sal, deptno from emp where ename = 'KING' or deptno = 20 and sal < 2000;

ORDER BY ORDER BYASCDESCORDER BYSELECTORDER BY select empno, ename, sal from emp order by sal;select empno, ename, sal, deptno from emp where deptno=30 order by sal;select empno, ename, sal*12 year, deptno from emp order by year;

select empno, ename, sal, deptno from emp order by sal,deptno;

select empno, ename, sal, deptno from emp order by deptno,sal;

ORDER BYSELECT

3000SQLlabl. sql7782100030002030"Employee""Monthly Salary1981AE

SQL

SELECT

SQLSQL: SQLOracle SQL

LOWER (column / expression)UPPER (column / expression) INITCAP (column / expression) CONCAT(column1 / expression1 , column2 / expression2)SUBSTR(column / expression, m [,n])m nm nLENGTH(column / expression)

DD-MON-RROracle47121199991231

SYSDATE SYSDATESYSDATESYSDATEDUALSYSDATE

select sysdate from dual;

'08-SEP-95'NEXT_DAY ('01-SEP-95','FRIDAY')'28-FEB-95'LAST_DAY ('01-FEB-95')19.6774194MONTHS_BETWEEN ('01-SEP-95','11-JAN-94')29-FEB-96'ADD_MONTHS (31-JAN-96',1)ResultFunction

NUMBERCHARACTERTO_CHARTO_NUMBERDATETO_CHARTO_DATE

TO_CHAR fm

select ename, to_char(hiredate,'YYYY-MM-FMDD') from emp;TO_CHAR(date, 'format_model')

F3(F2(F1(col,arg1),arg2),arg3)Step 1 = Result 1Step 2 = Result 2Step 3 = Result 3

NVL (exprl, expr2)NVL2 (exprl, expr2, expr3)NULLIF (exprl, expr2)COALESCE (exprl, expr2, ,exprn)

SELECT

:---

WHERE

select empno, ename, dname from emp,dept;

WHERE

SELECT table1.column, table2.columnFROM table1, table2WHERE table1.column1 = table2.column2;

EMPDEPTNODEPTDEPTNOEMPDEPTDEPTNO

nn-1

EMP,DEPT,LOCATIONS

ANDWHEREKINGWHERE

select empno, ename, dname from emp,dept where emp.deptno=dept.deptno and emp.ename=KING;

select ename,grade from emp,salgrade where emp.sal between losal and hisal;empSALSALGRADE

EMPSMITH

select worker.ename || ' works for ' || manager.ename from emp worker, emp manager where worker.MGR=manager.empno;

GROUP BYHAVING

AVGCOUNTMAXMINSUM

Maximum salary in EMPLOYEES table

EMPAverage salary in EMPLOYEES table for each department

HAVINGHAVING1.2.3.HAVING

HAVINGHAVINGgroup_condition HAVINGOracle1.2.3.HAVINGHAVINGGROUP BYGROUP BYHAVINGSELECT

HAVINGOracleOracleHAVINGSELECT ename, empno, salFROM empWHERE sal = (SELECT MIN(sal) FROM emp);800

SELECT empno, enameFROM empWHERE sal = (SELECT MIN(sal) FROM emp GROUP BY deptno);

Select empno, ename, salFrom empWhere sal > ANY (select MIN(sal) from emp group by deptno )OracleSelect empno, ename, salFrom empWhere sal in (950, 800, 1300)

DML(Data Manipulation Language )

INSERTtablecolumn value

()INSERT INTO EMP (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)

VALUES (7935, 'SCOTT', 'CLERK', 7782, '15-1-82', 1400, 0, 10);INSERT

INSERTNUMBER

VALUESNULLVALUESNULL VALUES( )INSERT INTO EMP (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, DEPTNO)

VALUES (7936, 'SCOTTB', 'CLERK', 7782, '15-1-82', 1500, 10);

SYSDATEINSERT INTO EMP (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, DEPTNO)

VALUES (7937, 'SCOTTB', 'CLERK', 7782, SYSDATE, 1520, 10);INSERT INTO EMP (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, DEPTNO)VALUES (7938, 'SCOTTC', 'CLERK', 7782, TO_DATE('2011-11-2','YYYY-MM-DD'), 1520, 10);

INSERTVALUESINSERTINSERT INTO BONUS

SELECT ENAME, JOB, SAL, SAL FROM EMP WHERE ENAME='SCOTT';

INSERTINSERTINTOVALUESINSERT INTO (SELECT EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO FROM EMP WHERE DEPTNO = 20)VALUES (7939, 'SCOTT6', 'CLERK', 7782, '15-1-82', 1400, 0, 10)

WITH CHECK OPTION WITH CHECK OPTIONINSERTUPDATEDELETE WITH CHECK OPTION20 SELECT10

INSERT INTO (SELECT EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO FROM EMP WHERE DEPTNO = 20 WITH CHECK OPTION)VALUES (7940, 'SCOTT6', 'CLERK', 7782, '15-1-82', 1400, 0, 10)

UPDATEtable column value condition

WHERE WHERE UPDATE EMP SET ENAME = 'SNOWFLY' WHERE EMPNO = 7938;

79387782UPDATE EMPSET JOB = (SELECT JOB FROM EMP WHERE EMPNO = 7782), SAL = (SELECT SAL FROM EMP WHERE EMPNO = 7782)WHERE EMPNO = 7938;

table

condition

WHERE WHEREDELETE FROM EMPWHERE ENAME = 'SCOTTB';

DELETEDELETE FROM EMP WHERE ENAME = (SELECT ENAME FROM BONUS)

DMLOracleSQL

DML SQL-COMMITROLLBACK-DDLDCL-SQL*Plus-

COMMIT ROLLBACK COMMITROLLBACK

-DDL-DCL-SQL*Plus,COMMITROLLBACK SQL*PIUS

COMMIT ROLLBACK SELECTDMLDML

COMMIT

ROLLBACK

Oracle

---DML--DDL

1-30 A-Za-z0-9_$ # Oracle

CREATE TABLE CREATE TABLE [schema.]table

(column datatype [DEFAULT expr] [, ...])

DEFAULT

SQL... hiredate DATE DEFAULT SYSDATE, ...

Oracle---Oracle Server-

CREATE TABLE AS subquery

CREATE TABLE COPY_EMPASSELECT * FROM EMP;

ALTER TABLE ALTER TABLE:

ALTER TABLE

DROP TABLEDROP TABLEDROP ANY TABLEDDLDROP TABLEDROP TABLE COPY_EMP;

rename copy_emp to copy2_emp;

TRUNCATE TABLE --TRUNCATE,DELETE

-NOT NULL-UNIQUE-PRIMARY KEY-FOREIGN KEY-CHECK

OracleSYS_Cn

---

constraint_name constraint_type

NOT NULL

UNIQUE

PRIMARY KEY PRIMARY KEY

PRIMARY KEY

PRIMARY KEY

FOREING KEY

INSERT INTO (SELECT EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO FROM EMP WHERE DEPTNO = 20)VALUES (7939, 'SCOTT6', 'CLERK', 7782, '15-1-82', 1400, 0, 10)INSERT INTO (SELECT EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO FROM EMP WHERE DEPTNO = 20 WITH CHECK OPTION)VALUES (7940, 'SCOTT6', 'CLERK', 7782, '15-1-82', 1400, 0, 10) SELECT INSERTUPDATEDELETE JHDML

Oracle DMLSELECT(DML)OracleDMLDML DML DML DDLCREATE TABLEDCL) CREATE TABLE COPY_EMPASSELECT * FROM EMP;rename copy_emp to copy2_emp;TRUNCATEDELETETRUNCATE(DDL)TRUNCATE

OracleSYS_CnnUSER_CONSTRAINTSCREATE TABLE EMP (EMPNO NUMBER(4) CONSTRAINT PK_EMP PRIMARY KEY,ENAME VARCHAR2(10),JOB VARCHAR2(9) NOT NULL,MGR NUMBER(4),HIREDATE DATE constraint hiredate NOT NULL,SAL NUMBER(7,2),COMM NUMBER(7,2),DEPTNO NUMBER(2) CONSTRAINT FK_DEPTNO REFERENCES DEPT);

PRIMARY KEYPRIMARY KEYPRIMARY KEYUNIQUEDEPARTMENTSDEPARTMENT_ID!J PRIMARY KEY DEPT_ID_PKPRIMARY KEYUNIQUEFOREIGN KEY (DEPARTMENT_IDEMPLOYEES (DEPARTMENTS (DEPARTMENT_IDNULLREFERENCES:

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基本的 SQL 语句