Use result of selection statement into another selection in stored procedure - sql-server

Question

How can I use the result of a select statement into another statement in a stored procedure in SQL Server? I am try to write this code
CREATE procedure [dbo].[ShowRequest] (#Id int)
AS
SELECT
Request.RequestId,
Request.UserId
INTO
reqTable
FROM
[User],[Request]
WHERE
Request.UserId = [User].UserId
AND
Request.RequestId = Id
/*another selection*/
SELECT
RequestProduct.ProductName
FROM
RequestProduct
/*ERROR:The multi-part identifier "ReqTable.id" could not be bound*/
WHERE
RequestProduct.RequestId = ReqTable.[id]

Answer 1

Try this:
CREATE procedure [dbo].[ShowRequest] (#Id int)
AS
SELECT
Request.RequestId,
Request.UserId
INTO
reqTable
FROM
[User],[Request]
WHERE
Request.UserId = [User].UserId
AND
Request.RequestId = Id
/*another selection*/
SELECT
ProductName
FROM
RequestProduct
WHERE
RequestId in
(
select id
from reqtable
)

Answer 2

It sounds like you actually just need to do a single selection:
SELECT
u.RequestId,
r.UserId,
rp.ProductName
FROM
[User] u
inner join
[Request] r
on
r.UserId = u.UserId
inner join
RequestProduct rp
on
rp.RequestId = r.RequestId
WHERE
r.RequestId = #Id
Generally, with SQL, you should decide what overall result you're trying to achieve, and then try to express it as a single statement - SQL Server's job (or any SQL product's) is to work out how best to construct the results. You shouldn't have to break down the problem into separate parts.

Answer 3

I don't know the etiquette here - this is a comment not a proposed answer but I want to make it easier for people to comment on my comment... downvote as appropriate... I don't want to just start a new question since I want the OP to see this.
You've got some alternatives but no one talked about why the first query didn't work or answered how to use the results of one query into another.
Why it didn't work: If the table "reqTable" existed and had a column named "id" at the time that your query was evaluated, SQL Server could have bound the name. You can use "eval" to put in sql that will be valid when it runs. For this problem that would be unjustifiably complex, but things like this must come up, I don't know if it's a regular tool in the toolbox of people who write a lot of stored procedures.
SQL Server 2005 and 2008 both have a feature called "CTE" you should read about that addresses the general question of "How do I use the results of one query in another query". They don't do anything subqueries absolutely can't do, but most of the time they are easier to write.

Answer 4

I have solved it. declare a table contains the result of first selection and use it in the second selection.
CREATE procedure [dbo].[ShowRequest] (#Id int)
AS
DECLARE #reqTable TABLE
(
ReqID int,
UserID int
)
INSERT INTO
#reqTable
SELECT
Request.RequestId AS 'ReqID',
Request.UserId
FROM
[User],[Request]
WHERE
Request.UserId = [User].UserId
AND
Request.RequestId = Id
/*another selection*/
SELECT
RequestProduct.ProductName
FROM
RequestProduct,#reqTable
WHERE
RequestProduct.RequestId = ReqID
Thanks for everyone who care about my question and spend his time to solve my problem