表中数据

MySQL中or和and的用法

SELECT * from student WHERE id = 1 or id = 2 AND age = 20;-- 查询结果是id = 2且age = 20或者id=1

 

SELECT * from student WHERE (id = 1 or id = 2 ) AND age = 20;-- 查询结果是 id=1或id=2 且age = 20

　

问题记录：要求查出 INVOICE_TITLE like ‘12%’或者CLIENT_NAME LIKE ‘%12%’的数据，结果前台一直报请求超时，发现数据多了将近20倍，SQL如下：

SELECT    *FROM    ewin_should_receive sr,    ewin_client_snap csWHERE    sr.client_snap_id = cs.idAND sr.b_enable = '1'AND cs.INVOICE_TITLE LIKE '%12%'OR cs.CLIENT_NAME LIKE '%12%'

正确SQL：

SELECT    *FROM    ewin_should_receive sr,    ewin_client_snap csWHERE    sr.client_snap_id = cs.idAND sr.b_enable = '1'AND (    cs.INVOICE_TITLE LIKE '%12%'    OR cs.CLIENT_NAME LIKE '%12%')