查询上一个查询的结果集

Question

I have a query for example Query1 = Select Name from table where some Criteria . Now this query returns a result set of course, what I want is to query the result set of this query, for example I only want the unique Names from the above query select Distinct(Name) from Query1 . I should mention that I know I can just use distinct in Query1 but this is just an example my real scenario is somewhat different, what I want to know is whether it's possible to query the result set of a previous query. I am using SQL Server 2012.

Answer 1

There are several ways to solve this:

1: create a view from the first query and run the second query on the view.

2: nest both queries, like this:

SELECT DISTINCT [Name]
FROM (
  SELECT [Name] 
  FROM table 
  WHERE some Criteria
) As InnerQuery

3: use a temporary table to store the resultset of the first query as suggested by wewesthemenace in the comments .

4: use CTE as suggested the thebreiflabb in the other answer to this post.

Personally, I would probably go with the first or second option, depending if you need to use the first query as stand alone as well.

Answer 2

You can use the WITH clause

WITH SomeClients AS (
    SELECT
        c.ID
    FROM Clients c
    WHERE c.Name LIKE '%hello%'
)

SELECT DISTINCT
    sc.ID
FROM SomeClients sc

Answer 3

You need WITH clause. The Syntax Is-

WITH someName AS(
 //Your Db Query
)
SELECT * FROM someName // OR Whatever you want

Answer 4

you can create a table to store the results temporarily and use that table in a new query

DECLARE @resultset table (
    ID   int identity(1,1) not null
  , name nvarchar(100)
)

Select top 50 application_Name
into  resultset
from Applications_ASIS