存储过程的简单问题，请高手指教

[nchen123]

create procedure HasPermission
(
@docId int,
@userId int,
@permissionId int,
@hasPermission int output -- 输出 0 或 1
)

as

declare @flagu int
declare @flagd int

select @flagu = GrantOrDeny from TDocPermission -- << -------------
where
docId = @docId
and deptOrUser = 'u'
and deptOrUserId = @userId
and permissionId = @permissionId

select @flagd = GrantOrDeny from TDocPermission
where
docId = @docId
and deptOrUser = 'd'
and permissionId = @permissionId
and deptOrUserId in
(
select deptId from TUser where userId = @userId
)


if @flagd = 0
select @hasPermission = 1
else
if @flagu = 1

-- 如果要在这里判断 @flagu 是否为空，也就是说上面箭头的 select 语句的查询结果为空，该怎么写这个判断语句 ?

....
go

[nchen123]

up

[txlicenhe]

If @flagu is null
...

[LoveSQL]

if not exists(select GrantOrDeny from TDocPermission
where
docId = @docId
and deptOrUser = 'u'
and deptOrUserId = @userId
and permissionId = @permissionId)

[quanyi]

if @flagu is null

[nchen123]

解决了，多谢！