mysql创建唯一字段_使用mysql创建唯一字段

1)在mysql中创建一张表 CREATE TABLE tbl_sequence ( name VARCHAR(50) NOT NULL, currentValue INT(11) NULL DEFAULT NULL, increment INT(11) NULL DEFAULT NULL, PRIMARY KEY (name) )

2)创建一个函数 DROP FUNCTION IF EXISTS nextval;

DELIMITER $

CREATE FUNCTION nextval (seq_name VARCHAR(50))

RETURNS INTEGER

BEGIN

DECLARE value INTEGER; SET VALUE &＃61; (SELECT currentValue from tbl_sequence where name &＃61; seq_name); if (VALUE IS NULL) then SET VALUE &＃61; 10000; INSERT INTO tbl_sequence(name, currentValue, increment) value(seq_name, VALUE, 1); END IF; UPDATE tbl_sequence SET currentValue &＃61; currentValue &＃43; increment WHERE name &＃61; seq_name; RETURN value;

END

$

DELIMITER ;

3)生成唯一键 select nextval(&＃39;20160708&＃39;);