Oracle常用语法

1,case用法

SELECT 
CASE 
  WHEN T.FLAG='0' THEN T.USERID
  WHEN T.FLAG='1' THEN T.ORGID
  ELSE NULL
END AS '标识'
FROM XTXMXX T

2,decode用法

--如果FLAG等于1,则转为USERID,如果为0,则转为ORGID,其他的为2
SELECT DECODE(T.FLAG,1,T.USERID,0,T.ORGID,2) FROM XTXMXX T ;

3,创建sequence 

-- Create sequence 创建sequence
create sequence T41_R_ITEM_FIELDKEY
minvalue 1
maxvalue 99999999999999
start with 10220
increment by 1
cache 20;

4,三种连接

--右连接  反方向连接
SELECT * 
FROM SX02_PROGRAM T,SX03_GL_ACCASS L
WHERE T.PROGRAMNO(+)=L.CITEM_ID;
--左链接
SELECT * 
FROM SX02_PROGRAM T,SX03_GL_ACCASS L
WHERE T.PROGRAMNO=L.CITEM_ID(+);

--特殊连接
SELECT T.PROGRAMNO,
(SELECT P.BONDNO FROM SX05_CONTRACT P WHERE P.PROGRAMNO=T.PROGRAMNO) 
FROM SX02_PROGRAM T,SX03_GL_ACCASS L
WHERE T.PROGRAMNO=L.CITEM_ID;

5,更新多列

--多列更新
UPDATE QJGL T SET (T.ZJQHZJRQ,T.ZJQHZJJE,T.LJQHZJJE)=
(
--此处只能查询单一值,故要关联
SELECT TT.ZJZJZJRQ,TT.ZJZJZJJE,TT.LJZJZJJE FROM QJGL TT
WHERE T.XTXMBH=TT.XTXMBH
);

6,快速创建表

--快速创建表语句
CREATE TABLE QJGL AS 
SELECT * FROM QJGLXX_ZQL T WHERE 1=0;

7,删除表

DROP TABLE TABLE_NAME;

8,删除用户

drop user istaudit cascade;

9.ROW_NUMBER分组排序

select cc.serialno,
       cc.objectno,
       cc.corpuspaysum,
       --PARTITION BY:分组   ORDER BY:排序  可正序倒序
       ROW_NUMBER() OVER(PARTITION BY cc.objectno ORDER BY cc.corpuspaysum desc) as rn
  from sx01_contract_paysource cc;

10.把数字转换为字符串仍保留0.格式 

--取两位小数,且把数字转换为字符串仍保留0.格式   
select to_char(round(0.326,2),90.99) || '%' as result from dual;

--不保留0.格式
select to_char(round(0.326,2)) || '%' as result from dual;

posted @ 2014-07-24 20:21  wanghx  阅读(166)  评论(0编辑  收藏  举报