SQL code
--
行列互转
/*
***************************************************************************************************************************************************** 以学生成绩为例子，比较形象易懂 整理人：中国风(Roy) 日期:2008.06.06 *****************************************************************************************************************************************************
*/
--
1、行互列
--
> --> (Roy)生成測試數據
if
not
object_id
(
'
Class
'
)
is
null
drop
table
Class
Go
Create
table
Class(
[
Student
]
nvarchar
(
2
),
[
Course
]
nvarchar
(
2
),
[
Score
]
int
)
Insert
Class
select
N
'
张三
'
,N
'
语文
'
,
78
union
all
select
N
'
张三
'
,N
'
数学
'
,
87
union
all
select
N
'
张三
'
,N
'
英语
'
,
82
union
all
select
N
'
张三
'
,N
'
物理
'
,
90
union
all
select
N
'
李四
'
,N
'
语文
'
,
65
union
all
select
N
'
李四
'
,N
'
数学
'
,
77
union
all
select
N
'
李四
'
,N
'
英语
'
,
65
union
all
select
N
'
李四
'
,N
'
物理
'
,
85
Go
--
2000方法:
动态:
declare
@s
nvarchar
(
4000
)
set
@s
=
''
Select
@s
=
@s
+
'
,
'
+
quotename
(
[
Course
]
)
+
'
=max(case when [Course]=
'
+
quotename
(
[
Course
]
,
''''
)
+
'
then [Score] else 0 end)
'
from
Class
group
by
[
Course
]
exec
(
'
select [Student]
'
+
@s
+
'
from Class group by [Student]
'
) 生成静态:
select
[
Student
]
,
[
数学
]
=
max
(
case
when
[
Course
]
=
'
数学
'
then
[
Score
]
else
0
end
),
[
物理
]
=
max
(
case
when
[
Course
]
=
'
物理
'
then
[
Score
]
else
0
end
),
[
英语
]
=
max
(
case
when
[
Course
]
=
'
英语
'
then
[
Score
]
else
0
end
),
[
语文
]
=
max
(
case
when
[
Course
]
=
'
语文
'
then
[
Score
]
else
0
end
)
from
Class
group
by
[
Student
]
GO
动态:
declare
@s
nvarchar
(
4000
)
Select
@s
=
isnull
(
@s
+
'
,
'
,
''
)
+
quotename
(
[
Course
]
)
from
Class
group
by
[
Course
]
exec
(
'
select * from Class pivot (max([Score]) for [Course] in(
'
+
@s
+
'
))b
'
) 生成静态:
select
*
from
Class pivot (
max
(
[
Score
]
)
for
[
Course
]
in
(
[
数学
]
,
[
物理
]
,
[
英语
]
,
[
语文
]
))b 生成格式:
/*
Student 数学 物理 英语 语文 ------- ----------- ----------- ----------- ----------- 李四 77 85 65 65 张三 87 90 82 78 (2 行受影响)
*/
--
----------------------------------------------------------------------------------------
go
--
加上总成绩(学科平均分)
--
2000方法:
动态:
declare
@s
nvarchar
(
4000
)
set
@s
=
''
Select
@s
=
@s
+
'
,
'
+
quotename
(
[
Course
]
)
+
'
=max(case when [Course]=
'
+
quotename
(
[
Course
]
,
''''
)
+
'
then [Score] else 0 end)
'
from
Class
group
by
[
Course
]
exec
(
'
select [Student]
'
+
@s
+
'
,[总成绩]=sum([Score]) from Class group by [Student]
'
)
--
加多一列(学科平均分用avg([Score]))
生成动态:
select
[
Student
]
,
[
数学
]
=
max
(
case
when
[
Course
]
=
'
数学
'
then
[
Score
]
else
0
end
),
[
物理
]
=
max
(
case
when
[
Course
]
=
'
物理
'
then
[
Score
]
else
0
end
),
[
英语
]
=
max
(
case
when
[
Course
]
=
'
英语
'
then
[
Score
]
else
0
end
),
[
语文
]
=
max
(
case
when
[
Course
]
=
'
语文
'
then
[
Score
]
else
0
end
),
[
总成绩
]
=
sum
(
[
Score
]
)
--
加多一列(学科平均分用avg([Score]))
from
Class
group
by
[
Student
]
go
--
2005方法:
动态:
declare
@s
nvarchar
(
4000
)
Select
@s
=
isnull
(
@s
+
'
,
'
,
''
)
+
quotename
(
[
Course
]
)
from
Class
group
by
[
Course
]
--
isnull(@s+',','') 去掉字符串@s中第一个逗号
exec
(
'
select [Student],
'
+
@s
+
'
,[总成绩] from (select *,[总成绩]=sum([Score])over(partition by [Student]) from Class) a pivot (max([Score]) for [Course] in(
'
+
@s
+
'
))b
'
) 生成静态:
select
[
Student
]
,
[
数学
]
,
[
物理
]
,
[
英语
]
,
[
语文
]
,
[
总成绩
]
from
(
select
*
,
[
总成绩
]
=
sum
(
[
Score
]
)
over
(partition
by
[
Student
]
)
from
Class) a
--
平均分时用avg([Score])
pivot (
max
(
[
Score
]
)
for
[
Course
]
in
(
[
数学
]
,
[
物理
]
,
[
英语
]
,
[
语文
]
))b 生成格式:
/*
Student 数学 物理 英语 语文 总成绩 ------- ----------- ----------- ----------- ----------- ----------- 李四 77 85 65 65 292 张三 87 90 82 78 337 (2 行受影响)
*/
go
--
2、列转行
--
> --> (Roy)生成測試數據
if
not
object_id
(
'
Class
'
)
is
null
drop
table
Class
Go
Create
table
Class(
[
Student
]
nvarchar
(
2
),
[
数学
]
int
,
[
物理
]
int
,
[
英语
]
int
,
[
语文
]
int
)
Insert
Class
select
N
'
李四
'
,
77
,
85
,
65
,
65
union
all
select
N
'
张三
'
,
87
,
90
,
82
,
78
Go
--
2000:
动态:
declare
@s
nvarchar
(
4000
)
select
@s
=
isnull
(
@s
+
'
union all
'
,
''
)
+
'
select [Student],[Course]=
'
+
quotename
(Name,
''''
)
--
isnull(@s+' union all ','') 去掉字符串@s中第一个union all
+
'
,[Score]=
'
+
quotename
(Name)
+
'
from Class
'
from
syscolumns
where
ID
=
object_id
(
'
Class
'
)
and
Name
not
in
(
'
Student
'
)
--
排除不转换的列
order
by
Colid
exec
(
'
select * from (
'
+
@s
+
'
)t order by [Student],[Course]
'
)
--
增加一个排序
生成静态:
select
*
from
(
select
[
Student
]
,
[
Course
]
=
'
数学
'
,
[
Score
]
=
[
数学
]
from
Class
union
all
select
[
Student
]
,
[
Course
]
=
'
物理
'
,
[
Score
]
=
[
物理
]
from
Class
union
all
select
[
Student
]
,
[
Course
]
=
'
英语
'
,
[
Score
]
=
[
英语
]
from
Class
union
all
select
[
Student
]
,
[
Course
]
=
'
语文
'
,
[
Score
]
=
[
语文
]
from
Class)t
order
by
[
Student
]
,
[
Course
]
go
--
2005:
动态:
declare
@s
nvarchar
(
4000
)
select
@s
=
isnull
(
@s
+
'
,
'
,
''
)
+
quotename
(Name)
from
syscolumns
where
ID
=
object_id
(
'
Class
'
)
and
Name
not
in
(
'
Student
'
)
order
by
Colid
exec
(
'
select Student,[Course],[Score] from Class unpivot ([Score] for [Course] in(
'
+
@s
+
'
))b
'
)
go
select
Student,
[
Course
]
,
[
Score
]
from
Class unpivot (
[
Score
]
for
[
Course
]
in
(
[
数学
]
,
[
物理
]
,
[
英语
]
,
[
语文
]
))b 生成格式:
/*
Student Course Score ------- ------- ----------- 李四 数学 77 李四 物理 85 李四 英语 65 李四 语文 65 张三 数学 87 张三 物理 90 张三 英语 82 张三 语文 78 (8 行受影响)
*/
补充如下：
Select aa.*, bb.[物理分数]
from
(select [Student],[数学分数]=Score from Class WHERE COURSE='数学') as aa,
(select [Student],[物理分数]=Score from Class WHERE COURSE='物理') as bb
where aa.[Student]=bb.[Student]
CREATE VIEW [hotel123].[vclass]
AS
SELECT Student, MAX(CASE WHEN [Course] = '数学' THEN [Score] ELSE 0 END) AS 数学, MAX(CASE WHEN [Course] = '物理' THEN [Score] ELSE 0 END)
AS 物理, MAX(CASE WHEN [Course] = '英语' THEN [Score] ELSE 0 END) AS 英语, MAX(CASE WHEN [Course] = '语文' THEN [Score] ELSE 0 END)
AS 语文
FROM hotel123.Class
GROUP BY Student
select *
from (select [Student],[Course]='数学',[Score]=[数学] from vClass union all
select [Student],[Course]='物理',[Score]=[物理] from vClass union all
select [Student],[Course]='英语',[Score]=[英语] from vClass union all
select [Student],[Course]='语文',[Score]=[语文] from vClass)t
order by [Student],[Course]
