如果用NoRows或Int命令？ sql

Question

我對最好的解決方法毫無頭緒。當前查詢很好。問題是我想if語句爲true，如果沒有行返回。我也不想兩次寫這個查詢，所以我怎麼寫這個if語句是真的並且運行？

IF (select AnInt from ATable where Cond) = expectedInt 
begin ... end 

Answer 1

如果NULLAnInt是不可能的，那麼你可以作出不匹配等於expectedInt

IF isnull((select AnInt from ATable where Cond), expectedInt) = expectedInt 

Answer 2

像這樣？

DECLARE @Test INT 

SELECT @Test = AnInt 
FROM ATable 
WHERE Cond 

IF @Test IS NULL OR @Test = expectedInt 
BEGIN 
... 
END 

Answer 3

IF Coalesce((select TOP 1 AnInt from ATable where Cond),expectedInt) = expectedInt 
begin 
end