Hello, I have followed David's suggestion (thank you!) -

On Wed, Aug 2, 2017 at 6:40 PM, David G. Johnston <
david.g.johns...@gmail.com> wrote:

> On Wed, Aug 2, 2017 at 8:58 AM, Alexander Farber <
> alexander.far...@gmail.com> wrote:
>
>> However if the user record is not found or the user already has vip_until
>> >= CURRENT_TIMESTAMP (i.e. the user has already purchased "vip status") I
>> would like to cancel the INSERT.
>>
>>
> ​You can "join" two DDL commands by using a Common Table Expression (CTE)
> (i.e., WITH / SELECT)​.  You would need to make it so the UPDATE happens
> first and if there are no results the INSERT simply becomes a no-op.
>
>
and the following works (if I change the function return type to VOID):

CREATE OR REPLACE FUNCTION words_buy_vip(
        in_sid text,
        in_social integer,
        in_tid text,
        in_item text,
        in_price float,
        in_ip inet)
        RETURNS void AS
$func$
        WITH cte AS (
                UPDATE    words_users u
                SET       vip_until = CURRENT_TIMESTAMP + interval '1 year'
                FROM      words_social s
                WHERE     s.sid    = in_sid
                AND       s.social = in_social
                AND       u.uid    = s.uid
                AND       (u.vip_until IS NULL OR u.vip_until <
CURRENT_TIMESTAMP)
                RETURNING
                          u.uid     AS uid,
                          in_sid    AS sid,
                          in_social AS social,
                          in_tid    AS tid,
                          in_price  AS price,
                          in_ip     AS ip
        )
        INSERT INTO words_payments (
                sid,
                social,
                tid,
                paid,
                price,
                ip
        ) SELECT
                sid,
                social,
                tid,
                CURRENT_TIMESTAMP,
                price,
                ip
        FROM cte
        -- RETURNING uid;

$func$ LANGUAGE sql;

But I wonder how to return the uid in the above statement?

(my original function returned integer uid)

Regards
Alex

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