1.类型对比
oracle | mysql |
int | int |
number(6,2) | decimal(6,2) |
date (sysdate) | timestamp (now()) |
varchar2(20) | varchar(20) |
2.常用函数
/* DATE_FORMAT(date,format) 根据format字符串格式化date值 */
select date_format('2013-09-21 14:01:20','%Y-%m-%d %H:%i:%s') from dual;
select case 2 when 1 then 1 when 2 then 2 else 0 end from dual;
select IFNULL(null,0) from dual;
3.分页
从第10条记录开始检索20条记录
select * from sys_option limit 10,20;
select * from table [查询条件] order by id limit ?,?;
以下语句是先排序后的分页(很好)
SELECT * FROM test_yutong ORDER BY ID DESC LIMIT 0,1;
order只能这么实现(没有mysql方便)
SELECT * FROM(SELECT * FROM TABLE_A ORDER BY ID DESC)B WHERE ROWNUM=1;
4.自定义序列函数(来源 http://www.oschina.net/code/snippet_110375_12231)
/* CREATE TABLE Sequence */
DROP TABLE IF EXISTS Sequence;
CREATE TABLE Sequence
(
name VARCHAR(32),
maxIndex INTEGER,
CONSTRAINT cst_Sequence_pk PRIMARY KEY (name, maxIndex)
);
/* FUNCTION nextval */
SET GLOBAL log_bin_trust_function_creators = 1;
DROP FUNCTION IF EXISTS nextval;
DELIMITER //
CREATE FUNCTION nextval(sequenceName VARCHAR(32))
RETURNS INTEGER
NOT DETERMINISTIC
CONTAINS SQL
BEGIN
DECLARE iMaxIndex INTEGER;
UPDATE Sequence SET maxIndex = maxIndex + 1 WHERE name = sequenceName;
SELECT maxIndex INTO iMaxIndex
FROM Sequence WHERE name = sequenceName;
RETURN iMaxIndex;
END
//
DELIMITER ;
/* 测试例子 */
INSERT INTO Sequence(NAME,maxIndex)VALUES('CK10_GHDJ',1);
SELECT nextval('CK10_GHDJ')FROM DUAL;
SELECT * FROM Sequence;
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