在此代碼其能夠分別互爲別名case語句等不能夠在巢式病例別名列名,使用SQL查詢
SELECT
id,
SUM(CASE
WHEN (a.place = 'CHN' AND a.salary = 20000)
THEN '1'
ELSE '0'
END) AS '20K Salary',
SUM(CASE
WHEN (a.place = 'CHN' and a.salary = 35000)
THEN '1'
ELSE '0'
END) AS '35K Salary'
FROM Employee a;
但嵌套CASE
當使用語句,
SELECT
id,
SUM(CASE
WHEN (a.place = 'CHN')
THEN (CASE
WHEN a.salary = 20000
THEN '1'
ELSE '0'
END) AS '20K Salary',
(CASE
WHEN a.salary = 35000
THEN '1'
ELSE '0'
END) AS '35K Salary'
END)
FROM Employee a;
它不可能執行查詢
如何找到Sum('True','False')'。沒有整數值被用於查詢中的sum()函數。 –
當你做'SUM'('YES')'時,你期望得到什麼? SUM可以應用於**數值** - 不是字符串,真的..... –
我需要在嵌套的情況下別名列 –