Re: Combining validation into main query

If you use EXISTS in the WHERE clause, you should come closer to what you
want realised.
For further help it would make it easier if you shared the whole queries
and perhaps a more detailed description of the goal you are trying to
accomplish.

HTH

Kind regards/met vriendelijke groet,

Serge Fonville

http://www.sergefonville.nl

Convince Microsoft!
They need to add TRUNCATE PARTITION in SQL Server
https://connect.microsoft.com/SQLServer/feedback/details/417926/truncate-partition-of-partitioned-table

2013/1/13 Robert James <srobertjames(at)gmail(dot)com>

> Typically, my web application does some initial validation, then, if
> it passes, does the actual query. For both performance and
> simplicity, I'd like to combine these all into one trip to Postgres.
> Ideally, I'd like to do this in SQL. If that's not possible, I could
> use PL/pgsql, though I'm not adept at it.
>
> Example #1:
> qry = "SELECT 1 FROM users WHERE username = ? AND PASSWORD = ?"
> if qry.count > 0
> qry = "SELECT ..."
>
> Example #2:
> qry = "SELECT 1 FROM users WHERE username = ? AND PASSWORD = ?"
> if qry.count > 0
> qry = "SELECT product WHERE ..."
> if qry.count > 0
> qry = "UPDATE product SET..."
>
> How can I combine these into one Postgres call? I'd like it to look
> something like:
>
> GET_PRODUCTS(username, password) -- Returns products, or -1 if
> username bad, -2 if password is bad
>
> UPDATE_PRODUCTS(username, password, productid, newval) -- Updates
> product, Returns 0 if good, -1 if username bad, -2 if password bad, -3
> if productid bad
>
>
> --
> Sent via pgsql-general mailing list (pgsql-general(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-general
>