sql语句中left join、inner join中的on与where的区别
摘要:
sql语句中left join、inner join中的on与where的区别 table a(id, type):id type ----------------------------------1 1 2 1 3 2 table b(id, class):id class ---------------------------------1 12 2sql语句1:select a.*, b.* from a left join b on a.id = b.id and a.type = 1;sql语句2:select a.*, b.* from a left join b on a.id 阅读全文
posted @ 2011-05-17 11:36 khh 阅读(333) 评论(1) 推荐(0) 编辑