[英]How to write sql query for following
這是我的表結構
在發布此問題之前,我嘗試過此操作:
select x.col1,x.col2 from
(
(select A from #t union all select C from #t) col1,
(select B from #t union all select D from #t) col2
)as x
您可以這樣嘗試。
Select A,B FROM #T
UNION ALL
Select C,D FROM #T WHERE C is not null
我會做
SELECT T1.A AS A_or_C, T1.B AS B_or_D FROM table_name T1
UNION
SELECT T2.C AS A_or_C, T2.D AS B_or_D FROM table_name T2
如此絕對清楚。
干杯
select A, B from TABLE union select C, D from TABLE
select A, B from table_name
union
select C,D from table_name
嘗試這個:
SELECT A as Name,B as Value FROM x
UNION ALL
SELECT C,D FROM x
WHERE C IS NOT NULL
結果將是:
NAME VALUE
AA 0.5
BB 0.5
CC 0.3
DD 0.2
BB 0.3
CC 0.5
請參見SQL Fiddle中的結果
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