在论坛中出现的比较难的sql问题：39(动态行转列 动态日期列问题)

原文: 在论坛中出现的比较难的sql问题：39(动态行转列 动态日期列问题)

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。

求一SQL语句。

http://bbs.csdn.net/topics/390496661

   
   
create table #tab
(
col1 char( 10),
col2 char( 10),
item char( 10),
num int,
[ Date] varchar( 10))
insert #tab values( 'AAA', 'BBB', 'A', 50, '2013-06-10')
insert #tab values( 'ABB', 'BGG', 'B', 30, '2013-06-10')
insert #tab values( 'AAA', 'BBB', 'C', 80, '2013-06-13')
  
  

我的解法：

   
   
create table tab
(
col1 char( 10),
col2 char( 10),
item char( 10),
num int,
[ Date] varchar( 10)
)

insert tab values( 'AAA', 'BBB', 'A', 50, '2013-06-10')
insert tab values( 'ABB', 'BGG', 'B', 30, '2013-06-10')
insert tab values( 'AAA', 'BBB', 'C', 80, '2013-06-13')




--动态生成sql语句
declare @start_date varchar( 10) = '2013-06-01',
@end_date varchar( 10) = '2013-06-30';

declare @ date varchar( 10),
@ sql varchar( max) = '',
@sql1 varchar( 8000),
@sql2 varchar( 8000);

set @ date = @start_date;

set @sql1 = 'select case when rownum = 1 then col1 else '''' end as col1,
case when rownum = 1 then col2 else '''' end as col2,
item'

set @sql2 = 'select col1,col2,item,row_number() over(partition by col1,col2
order by item) as rownum'


while @ date <= @end_date
begin
set @sql1 = @sql1 + ',v_' + REPLACE( right(@ date, 5), '-', '') +
' as ''' + CAST( DATEPART( month,@ date) as varchar) + '/' +
CAST( DATEPART( day,@ date) as varchar) + '''';
set @sql2 = @sql2 + ',SUM(case when date =''' + @ date +
''' then num else 0 end) as v_' +
REPLACE( right(@ date, 5), '-', '')

set @ date = CONVERT( varchar( 10), dateadd( day, 1,@ date), 120)
end


set @ sql = @sql1 + ' from (' +
@sql2 + ' from tab
group by col1,col2,item' +
') v'

--生产的动态sql语句
select @ sql


exec(@ sql)
  
  

上面由于是动态生成语句，所以不能用局部的临时表，所以建了一个表。

下面是动态生成的sql语句，经过了格式化：

   
   
select case when rownum = 1 then col1 else '' end as col1,
case when rownum = 1 then col2 else '' end as col2,
item,

v_0601 as '6/1',v_0602 as '6/2',v_0603 as '6/3',
v_0604 as '6/4',v_0605 as '6/5',
v_0606 as '6/6',v_0607 as '6/7',
v_0608 as '6/8',v_0609 as '6/9',
v_0610 as '6/10',v_0611 as '6/11',
v_0612 as '6/12',v_0613 as '6/13',
v_0614 as '6/14',v_0615 as '6/15',
v_0616 as '6/16',v_0617 as '6/17',
v_0618 as '6/18',v_0619 as '6/19',
v_0620 as '6/20',v_0621 as '6/21',
v_0622 as '6/22',v_0623 as '6/23',
v_0624 as '6/24',v_0625 as '6/25',
v_0626 as '6/26',v_0627 as '6/27',
v_0628 as '6/28',v_0629 as '6/29',
v_0630 as '6/30'
from
(
select col1,col2,item,

row_number() over( partition by col1,col2 order by item) as rownum,

SUM( case when date = '2013-06-01' then num else 0 end) as v_0601,
SUM( case when date = '2013-06-02' then num else 0 end) as v_0602,
SUM( case when date = '2013-06-03' then num else 0 end) as v_0603,
SUM( case when date = '2013-06-04' then num else 0 end) as v_0604,
SUM( case when date = '2013-06-05' then num else 0 end) as v_0605,
SUM( case when date = '2013-06-06' then num else 0 end) as v_0606,
SUM( case when date = '2013-06-07' then num else 0 end) as v_0607,
SUM( case when date = '2013-06-08' then num else 0 end) as v_0608,
SUM( case when date = '2013-06-09' then num else 0 end) as v_0609,
SUM( case when date = '2013-06-10' then num else 0 end) as v_0610,
SUM( case when date = '2013-06-11' then num else 0 end) as v_0611,
SUM( case when date = '2013-06-12' then num else 0 end) as v_0612,
SUM( case when date = '2013-06-13' then num else 0 end) as v_0613,
SUM( case when date = '2013-06-14' then num else 0 end) as v_0614,
SUM( case when date = '2013-06-15' then num else 0 end) as v_0615,
SUM( case when date = '2013-06-16' then num else 0 end) as v_0616,
SUM( case when date = '2013-06-17' then num else 0 end) as v_0617,
SUM( case when date = '2013-06-18' then num else 0 end) as v_0618,
SUM( case when date = '2013-06-19' then num else 0 end) as v_0619,
SUM( case when date = '2013-06-20' then num else 0 end) as v_0620,
SUM( case when date = '2013-06-21' then num else 0 end) as v_0621,
SUM( case when date = '2013-06-22' then num else 0 end) as v_0622,
SUM( case when date = '2013-06-23' then num else 0 end) as v_0623,
SUM( case when date = '2013-06-24' then num else 0 end) as v_0624,
SUM( case when date = '2013-06-25' then num else 0 end) as v_0625,
SUM( case when date = '2013-06-26' then num else 0 end) as v_0626,
SUM( case when date = '2013-06-27' then num else 0 end) as v_0627,
SUM( case when date = '2013-06-28' then num else 0 end) as v_0628,
SUM( case when date = '2013-06-29' then num else 0 end) as v_0629,
SUM( case when date = '2013-06-30' then num else 0 end) as v_0630
from tab
group by col1,col2,item
) v