Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 365
  • Last Modified:

SQL UNION Operator

Hi Expert,

Code is here

SET @SQL_MAIN = @SQL_MAIN + @SQL_1

EXECUTE SP_EXECUTESQL @SQL_MAIN

----------SQL_MAIN  is main query, @SQL_1 inner join table A, @SQL_2 inner join table B

I want Union  @SQL_2, how to do it?

thanks in advance
0
dshi15
Asked:
dshi15
  • 2
  • 2
2 Solutions
 
lcohanDatabase AnalystCommented:
I suggest you rather use CTE instead of @sql2 - just put all that query or even both in CTE and use them in a UNION afterwards.

http://msdn.microsoft.com/en-us/library/ms190766(v=sql.105).aspx
here's one with UNION ALL but you can just drop the ALL

http://stackoverflow.com/questions/8985609/union-all-in-cte

more complicated recursive CTE examples here:
http://stackoverflow.com/questions/3159192/sql-server-2008-cte-recursion
0
 
dshi15Author Commented:
Why  "use CTE instead of @sql2" ?

in my query string, I pass a lot of variable to the query.
0
 
Guy Hengel [angelIII / a3]Billing EngineerCommented:
as it's not clear (to me) what you want to achieve, can you please show examples of the values of @main, @sql1, @sql2 and the requested end result
0
 
dshi15Author Commented:
@main=select * from table A inner join table B

@sql1= @main + " inner join table C"

@sql2= @main + " inner join table D"

Something like that.

I got Union All and result correct, i don't know why use CTE? any better?

Thanks.
0
 
Guy Hengel [angelIII / a3]Billing EngineerCommented:
that looks fine, actually, in the basics, so it should work
the question is: why you want/need dynamic sql.
with CTE, you would avoid dynamic sql which may give you issues at other levels.

;WITH main AS ( Select * from tableA inner join table B ON ... )
SELECT * from main join table_c on  ...
UNION ALL
SELECT * from main join table_d on  ...

Open in new window

0

Featured Post

Hire Technology Freelancers with Gigs

Work with freelancers specializing in everything from database administration to programming, who have proven themselves as experts in their field. Hire the best, collaborate easily, pay securely, and get projects done right.

  • 2
  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now