選擇AS不是在IB的工作

Question

工作

select payeeid, EXTRACT(WEEKDAY FROM checkdate) as DOW, 
(bankcleared - checkdate) as DateDiff 
from Master 
where (bankcleared is not null) 
order by payeeid, DOW, DateDiff 

加入DateDiff到Where - 不工作

select payeeid, EXTRACT(WEEKDAY FROM checkdate) as DOW, 
(bankcleared - checkdate) as DateDiff 
from Master 
where (bankcleared is not null) AND (DateDiff >= 1) 
order by payeeid, DOW, DateDiff 

Answer 1

只能在GROUP BY，ORDER BY或HAVING子句中使用列別名。

標準SQL不允許引用WHERE子句中的列別名。這種限制是因爲在執行WHERE代碼時，列值可能還沒有確定。

試試這個

select payeeid, EXTRACT(WEEKDAY FROM checkdate) as DOW, 
(bankcleared - checkdate) as DateDiff 
from Master 
where (bankcleared is not null) AND ((bankcleared - checkdate)>= 1) 
order by payeeid, DOW, DateDiff 

欲瞭解更多信息請通過這些鏈接

Can you use an alias in the WHERE clause in mysql?

Unknown Column In Where Clause

Answer 2

select payeeid, 
     EXTRACT(WEEKDAY FROM checkdate) as DOW, 
     (bankcleared - checkdate) as DateDiff 
from Master 
WHERE (bankcleared is not null) 
AND ((bankcleared - checkdate)>= 1) 
Order by payeeid, DOW, DateDiff