最近,在论坛中,遇到了不少比较难的sql问题,虽然自己都能解决,但发现过几天后,就记不起来了,也忘记解决的方法了。
所以,觉得有必要记录下来,这样以后再次碰到这类问题,也能从中获取解答的思路。
1、求SQL遍历截取字符串
http://bbs.csdn.net/topics/390648078
从数据库中读取某一张表(数据若干),然后将某一字段进行截取。
比如:
字段A 字段B
a/a/c x
a/b/c x
切出来就变成:
字段1 字段2 字段3 字段B
a a c x
b b c x
数据不止一条 ,是遍历切取,求完整sql(从读取到遍历到截取到输出),求教。
另外还需要把列头进行排序,结果也需要按照字段1,字段2...进行排序
我的解法:
if object_id('[tb]') is not null drop table [tb] go create table [tb](A varchar(40),B varchar(10)) insert [tb] select 'xx/xx/xx/xx/xx/xx','x' union all select 'yy/yy/yy/yy/yy/yy','x' go if OBJECT_ID('tempdb..#temp1') is not null drop table #temp1 if OBJECT_ID('tempdb..#temp2') is not null drop table #temp2 select *,IDENTITY(int,1,1) id into #temp1 from tb declare @sql nvarchar(3000) declare @orderby nvarchar(100) set @sql = ''; set @orderby = ''; ;with t as ( select ID, SUBSTRING(t.A, number ,CHARINDEX('/',t.a+'/',number)-number) as v, b, row_number() over(partition by id order by @@servername) as rownum from #temp1 t,master..spt_values s where s.number >=1 and s.type = 'P' and SUBSTRING('/'+t.A,s.number,1) = '/' ) select * into #temp2 from t select @sql = @sql + ',max(case when rownum = '+CAST(rownum as varchar)+ ' then v else null end) as 列'+CAST(rownum as varchar) , @orderby = @orderby + ',列'+CAST(rownum as varchar) from #temp2 group by rownum order by rownum --加了排序 set @sql = 'select '+STUFF(@sql,1,1,'')+ ',b' + ' from #temp2 group by id,b order by '+ stuff(@orderby,1,1,'') --select @sql exec(@sql) /* 列1 列2 列3 列4 列5 列6 b xx xx xx xx xx xx x yy yy yy yy yy yy x */