Re: Converting T-SQL to PostgreSQL

Hello

2009/11/5 maboyz <thabani(dot)moyo(at)distributel(dot)ca>:
>
> I am trying to re write the following stored proc as a postgresql
> function......but am new to postgres and it is kind of getting really
> confusing trying to learn and let alone understand the syntax:
>
> CREATE PROCEDURE [dbo].[GetAppAvailability]
>        @AuditAvailable         bit output,
>        @BillingAvailable       bit output,
>        @ReturnValue            int output
> AS
> SET NOCOUNT ON
>
> set @AuditAvailable = (select app_Status from AppAvailability where
> app_Functionality = 'Audit')
> set @BillingAvailable = (select app_Status from AppAvailability where
> app_Functionality = 'Billing')
>
> Set @ReturnValue = @@Error
>
> I have this in postgres but obviously it is not correct:
>
> CREATE OR REPLACE FUNCTION GetAppAvailability(OUT auditAvailable character
> varying, OUT billingAvailable character varying)
>   AS
> $BODY$
>     set $1 = (select "app_Status" from "AppAvailability" where
> "app_Functionality" = 'Audit');
>    set $2 = (select "app_Status" from "AppAvailability" where
> "app_Functionality" = 'Billing');
>        $BODY$
>  LANGUAGE 'sql' VOLATILE
>  COST 100;
>

You can use SQL functions, but SQL has not assign statement. So you
have to use plpgsql language.
http://www.postgresql.org/docs/8.4/interactive/plpgsql.html

You code should be

CREATE OR REPLACE FUNCTION GetAppAvailability(OUT auditAvailable character
varying, OUT billingAvailable character varying)
AS
$BODY$
$1 = (select "app_Status" from "AppAvailability" where
"app_Functionality" = 'Audit');
$2 = (select "app_Status" from "AppAvailability" where
"app_Functionality" = 'Billing');
$BODY$
LANGUAGE plpgsql VOLATILE

Usually is better if you forgot on T-SQL and try to learn language again.

there are some good advices:

a) don't use camel notation for identifiers
b) don't use case sensitive identifiers like "some"
c) don't create "SELECT only" functions

Why do you use function?

use view:
CREATE VIEW GetAppAvailability AS
SELECT (SELECT "app_Status"
FROM "AppAvailability"
WHERE "app_Functionality" = 'Audit'),
(SELECT "app_Status"
FROM "AppAvailability"
WHERE "app_Functionality" = 'Billing');

some link
http://www.postgres.cz/index.php/PL/pgSQL_%28en%29

regards
Pavel Stehule
>
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