Re: Converting T-SQL to PostgreSQL

2009/11/5 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
> 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
>  $BODY$
BEGIN

>     $1 = (select "app_Status" from "AppAvailability" where
>  "app_Functionality" = 'Audit');
>    $2 = (select "app_Status" from "AppAvailability" where
>  "app_Functionality" = 'Billing');

END
>        $BODY$
>  LANGUAGE plpgsql VOLATILE
>

sorry, I left out main block. plpgsql function have to have block etc
BEGIN .... END;

> 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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>>
>>
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>