摘要:
表的查询操作 select * from 表 *效率低 select * from 表 where id > 1 select nid,name,gender as gg from 表 where id > 1 as相当于取别名,别名为gg select count(id) from userinfo5; 查询表内有多少条数据 select * from tb12; select id,name 阅读全文
posted @ 2019-12-18 19:03
Fastisslow
阅读(1120)
评论(0)
推荐(0)