在此代码其能够分别互为别名case语句等不能够在巢式病例别名列名,使用SQL查询
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
当使用语句,
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;
它不可能执行查询
如何找到Sum('True','False')'。没有整数值被用于查询中的sum()函数。 –
当你做'SUM'('YES')'时,你期望得到什么? SUM可以应用于**数值** - 不是字符串,真的..... –
我需要在嵌套的情况下别名列 –