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。
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
-
*/