Subject | RE: [firebird-support] Nested Joins or Temp Tables |
---|---|
Author | Paul Lopez |
Post date | 2011-04-07T04:11:52Z |
Hi,
Select t.fielda, d.fieldb <-- this gets the t2.fieldb
From sometable t
Join ( // derived table
Select t2.fieldb, t2.fieldc as fieldx
From anothertable t2
Where somecondition=true
) d on d.fieldx = t.fieldy
Where otherconditions=true
Hope this helps.
Paul.
> Hey. FB Newb here. Come from strictly a SQL Server background. I amWe regularly do this...
> attempting to optimize some queries and procedures by either
>
> A) Creating a temp table, inserting key values from a small set of records,
> then using the temp table as my initial join for child tables
>
> or
>
> B) Using a nested select (derived table) to essentially do the same thing
>
> I can not seem to find anywhere online whether this is even supported and if
> it is, the correct syntax. We are using FB 1.5.
>
> Any help is greatly appreciated.
> JP
>
Select t.fielda, d.fieldb <-- this gets the t2.fieldb
From sometable t
Join ( // derived table
Select t2.fieldb, t2.fieldc as fieldx
From anothertable t2
Where somecondition=true
) d on d.fieldx = t.fieldy
Where otherconditions=true
Hope this helps.
Paul.