[MSSQL] IF EXISTS

最近看到一個不太直覺的 stored procedure

CREATE PROCEDURE OneProcedure (...)
AS
IF (SELECT COUNT(*) FROM OneTable) = 0
RETURN 0;
ELSE
RETURN 1;
GO



其實可以用 EXISTS 改寫。

IF EXISTS (SELECT * FROM OneTable) ...



如果只是要下 SQL:

select case when exists(select 1 from OneTable) then 1 else 0 end