SQL server 使用 unpivot 函数
您将如何使用 SQL 获得以下输出?
How would you obtain the following output using SQL?
Type: Value Type2 Value2
p_01 1 ofpk_01 1
p_02 2 ofpk_02 2
p_03 3 ofpk_03 3
表结构
create table test(p_01 int,
p_02 int,
p_03 int,
ofpk_01 int,
ofpk_02 int,
ofpk_03 int)
SQL 小提琴链接
这是否可以使用 unpivot 功能?这是我到目前为止所得到的:
Is this possible with unpivot function? here is what I've got so far:
推荐答案
另一种解决方案是使用CROSS APPLY
:
Another solution is to use CROSS APPLY
:
SELECT ca.*
FROM dbo.Test x
CROSS APPLY
(
SELECT 'p_01' AS Type1, x.p_01 AS Value1, 'ofpk_01' AS Type2, x.ofpk_01 AS Value2 UNION ALL
SELECT 'p_02' AS Type1, x.p_02 AS Value1, 'ofpk_02' AS Type2, x.ofpk_02 AS Value2 UNION ALL
SELECT 'p_03' AS Type1, x.p_03 AS Value1, 'ofpk_03' AS Type2, x.ofpk_03 AS Value2
) ca;
SQL 小提琴
或者如果 2008+ 可以缩短为
Or if 2008+ this can be shortened to
SELECT ca.*
FROM dbo.Test x
CROSS APPLY
(VALUES
('p_01', x.p_01, 'ofpk_01', x.ofpk_01),
('p_02', x.p_02, 'ofpk_02', x.ofpk_02),
('p_03', x.p_03, 'ofpk_03', x.ofpk_03)
) ca(Type1, Value1, Type2, Value2);
SQL 小提琴
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