文章分类 - sql

数据库经验

SQl group by用法 case when拆分列用法 having子句筛选行合并

摘要：case when拆分列select CONVERT(varchar(10),createtime,120) as gr_date ,case when status=1 then count(id) end as made,case when status=2 then count(id) end as unmadefrom ms_user_0 as ms2 --where mobile='15088719610' group by CONVERT(varchar(10),createtime,120),statusorder by CONVERT(varchar(10),c 阅读全文

posted @ 2014-01-23 01:30 那夜我还很年幼~ 阅读(9631) 评论(0) 推荐(0)

sql中时间处理，多个字符串转换成字节处理，删除表里的重复数据

摘要：字符串操作--字符串操作select DATALENGTH(title) from o_youhuiquan --字段的长度select CONVERT(TEXT,title) from o_youhuiquan --转换成TEXT ，使一个汉字占两个字节（16位）select SUBSTRING(title,1,9) from o_youhuiquan --字符个数截取select SUBSTRING(CONVERT(TEXT,title),1,40) from o_youhuiquan --按字节截取时间操作select DateAdd(dd,-2,intime) from o_you.. 阅读全文

posted @ 2013-05-29 23:42 那夜我还很年幼~ 阅读(349) 评论(0) 推荐(0)