Postgres Pro
Downloads
Home   >   mailing lists

Unused CTE affects result set - Mailing list pgsql-general

From Gabriel Sánchez
Subject Unused CTE affects result set
Date
Msg-id CANHuRqHUR+a0TEF7WXLNN1+_=6CjET-jtu=QFuEPJ875oMHC7A@mail.gmail.com
Whole thread Raw
Responses Re: Unused CTE affects result set
List pgsql-general
Tree view
Dear Postgres community,

I'm seeing unintuitive behavior with a query structured as follows:

WITH used_cte (SELECT a, b, c FROM t1 ...)
, unused_cte (SELECT d, e, f FROM t2 ...)
SELECT * FROM used_cte ...
-- returns no results

WITH used_cte (SELECT a, b, c FROM t1 ...)
-- , unused_cte (SELECT d, e, f FROM t2 ...)
SELECT * FROM used_cte ...
-- returns results

I don't understand why the presence of a CTE that ends up not being included in the final query affects the result set.  Could this be a bug, or is there something I don't understand?

PostgreSQL 14.9 (Ubuntu 14.9-0ubuntu0.22.04.1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, 64-bit

Thanks,
Gabriel


pgsql-general by date:

Previous
From: Adrian Klaver
Date:
Subject: Re: PostgreSQL statistics
Next
From: Adrian Klaver
Date:
Subject: Re: Unused CTE affects result set