CREATE PROCEDURE forums_DisallowedName_CreateUpdateDelete ( @Name nvarchar(64), @Replacement nvarchar(64), @DeleteName bit = 0 ) AS SET NOCOUNT ON -- 上面一句的作用是‘使返回的结果中不包含有关受 Transact-SQL 语句影响的行数的信息。’，是不是可以理解为：＠＠ROWCOUNT将返回零 if( @DeleteName > 0 ) BEGIN DELETE FROM forums_DisallowedNames WHERE DisallowedName = @Name END ELSE BEGIN UPDATE forums_DisallowedNames SET DisallowedName = @Replacement WHERE DisallowedName = @Name if( @@rowcount = 0 ) -- 如果我上面的理解正确的话，那上面那IF里的表达式不是恒真？ -- 如果我上面的理解不正确的话，那 SET NOCOUNT ON的真正作用是什么呢？ BEGIN INSERT INTO forums_DisallowedNames ( DisallowedName ) VALUES ( @Name ) END END GO