CREATE TABLE [dbo].[_Test] (
2) Insert 2 sample records into it
insert into _Test(col1, status)
4) Now try to execute it
Oh, where's another records?
6) And this is quoted from MSSQL BOL (Book On-Line) / T-SQL Reference:
To determine if an expression is NULL, use IS NULL or IS NOT NULL rather than comparison operators (such as = or !=). Comparison operators return UNKNOWN if either or both arguments are NULL.
Now, you realized you used the comparison operators to execute it unknowingly!
CREATE PROCEDURE dbo._spTest
execute _spTest 1
execute _spTest NULL