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Oracle基础函数
- SELECT LOWER('Hello World') 转小写,
- UPPER('Hello World') 转大写,
- INITCAP('hello world') 首字母大写
- FROM DUAL;
-
- SELECT CONCAT('Hello','World') 字符连接
- FROM DUAL;
-
- SELECT SUBSTR('Hello World',3) FROM DUAL;
- SELECT SUBSTR('Hello World',3,4) FROM DUAL;
-
- SELECT LENGTH('China') 字符数,
- LENGTHB('China') 字节数
- FROM DUAL;
-
- SELECT INSTR('Hello World','ll')
- FROM DUAL;
-
- SELECT LPAD('abcd',10,'*') 左填充,
- RPAD('abcd',10,'*') 右填充
- FROM DUAL;
-
- SELECT TRIM('H' FROM 'Hello WorldH')
- FROM DUAL;
-
- SELECT REPLACE('Hello World','l','*')
- FROM DUAL;
-
- SELECT ROUND(45.926,2) 四舍五入,
- TRUNC(45.926,2) 截断,
- MOD(1600,300) 求余
- FROM DUAL;
-
- SELECT ROUND(45.923,0) 整数位,
- ROUND(45.923,-1) 十位,
- ROUND(45.923,-2) 百位
- FROM DUAL;
-
- SELECT SYSDATE
- FROM DUAL;
-
- SELECT TO_CHAR(SYSDATE,'YYYY-MM-DD HH24:MI:SS')
- FROM DUAL;
-
- SELECT SYSDATE - 1 昨天,
- SYSDATE 今天,
- SYSDATE + 1 明天
- FROM DUAL;
-
- SELECT EMPNO,ENAME,SYSDATE - HIREDATE 天
- FROM EMP;
-
- SELECT EMPNO,ENAME,SYSDATE - HIREDATE 天,
- (SYSDATE - HIREDATE)/7 星期, (SYSDATE - HIREDATE)/30 月
- FROM EMP;
-
- SELECT (SYSDATE-HIREDATE)/30 方式一,
- MONTHS_BETWEEN(SYSDATE,HIREDATE) 方式二
- FROM EMP;
-
- SELECT ADD_MONTHS(SYSDATE,1) 下个月,
- ADD_MONTHS(SYSDATE,123) "123个月后"
- FROM DUAL;
-
- SELECT LAST_DAY(SYSDATE)
- FROM DUAL;
-
- SELECT NEXT_DAY(SYSDATE,'星期五')
- FROM DUAL;
-
- SELECT ROUND(SYSDATE,'MONTH') 月,
- ROUND(SYSDATE,'YEAR')
- FROM DUAL;
-
- SELECT TRUNC(SYSDATE,'MONTH') 月,
- ROUND(SYSDATE,'YEAR')
- FROM DUAL;
-
- SELECT *
- FROM EMP
- WHERE HIREDATE =
- TO_DATE('1982-01-23','YYYY-MM-DD');
-
- SELECT TO_CHAR(SYSDATE,
- 'YYYY-MM-DD HH24:MI:SS"今天是"DAY')
- FROM DUAL;
-
- SELECT EMPNO,ENAME,
- TO_CHAR(SAL,'L9,999.99')
- FROM EMP;
-
- SELECT ENAME,SAL*12+NVL2(COMM,COMM,0) 年收入
- FROM EMP;
-
- SELECT NULLIF('ABC','ABC'),NULLIF('A','AG')
- FROM DUAL;
-
- SELECT ENAME,COMM,SAL,COALESCE(COMM,SAL)
- FROM EMP;
-
- SELECT ENAME,JOB,SAL 涨前工资,
- CASE JOB
- WHEN 'PRESIDENT' THEN SAL + 1000
- WHEN 'MANAGER' THEN SAL + 600
- ELSE SAL + 400
- END
- 涨后工资
- FROM EMP;
- SELECT ENAME,JOB,SAL 涨前工资,
- DECODE(JOB,'PRESIDENT',SAL + 1000,
- 'MANAGER',SAL + 600, SAL + 400) 涨后工资
- FROM EMP;
-
-
- SELECT TO_CHAR('AABBCC')
- FROM DUAL;
-
- SELECT TO_CHAR(SYSDATE,'YYYY-MM-DD HH24:MI:SS')
- FROM DUAL;
-
- SELECT TO_CHAR(-100,'L999G99D99MI')
- FROM DUAL;
-
- SELECT TO_DATE(2454334,'J')
- FROM DUAL;
-
- SELECT TO_NUMBER('-100.00','9G999D99')
- FROM DUAL;
-
- SELECT DECODE('a2','a1','true1','a2','true2',
- 'default')
- FROM DUAL;
-
- SELECT GREATEST(14,3,5,3)
- FROM DUAL;
-
- SELECT LEAST(12,3,5,5)
- FROM DUAL;
-
- SELECT NULLIF('A','B'),NULLIF('A','A')
- FROM DUAL;
-
- SELECT NVL(NULL,'12')
- FROM DUAL;
-
- SELECT NVL2('A','B','C') ,
- NVL2(NULL,'B','C')
- FROM DUAL;
-
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原文地址:https://www.cnblogs.com/guanghe/p/6054105.html
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