Re: help w/ SRF function

On Mon, 2007-09-17 at 09:21 +0800, Ow Mun Heng wrote:
> Hi,
>
> I want to use a SRF to return multi rows.
>
> current SRF is pretty static.
>
> create type foo_type as (
> id smallint
> data1 int
> data2 int
> )
>
> CREATE OR REPLACE FUNCTION foo_func()
>   RETURNS SETOF foo AS
> $BODY$
>     SELECT
>     TRH.ID,
>     TRH.data1,
>     TRH.data2,
>     FROM D
>     INNER JOIN  TS
>          ON TS.id = D.id
>     inner join TRH
>          on ts.id = trh.id
>     WHERE D.start_timestamp BETWEEN '8/1/2007' AND '9/8/2007'
>     And D.code IN ('ID_123')
> $BODY$
> LANGUAGE 'sql' IMMUTABLE STRICT;
>
> I would like for the above to be a little bit more dynamic in that the
> start_timestamp and the code can be input-fields.
>
> eg:
>
> CREATE OR REPLACE FUNCTION foo_func(fromdate timestamp, todate
> timestamp, code text)
>   RETURNS SETOF foo AS
> $BODY$
>     SELECT
>     TRH.ID,
>     TRH.data1,
>     TRH.data2,
>     FROM D
>     INNER JOIN  TS
>          ON TS.id = D.id
>     inner join TRH
>          on ts.id = trh.id
>     WHERE D.start_timestamp BETWEEN fromdate AND todate
>     And D.code IN (code)
> $BODY$
> LANGUAGE 'sql' IMMUTABLE STRICT;
>
> How can I go about this this? The above will fail due to missing columns
> fromdate/todate/code.
>
> Or should I use plpgsql as SQL cannot handle variable substitution?
>
> What about doing  dynamic SQL eg:
>
> Dsql = select X,Y,Z from foo, join bar on bar.a = foo.a
>        where D.start_timestamp between ' || fromdate ||' and ' ||
> todate||'
>
> execute DSQL
>
> Thanks for any/all help.


Seems like I found this after I posted the question. (Doh! Why does this
always happen)

Variable substition can happen using $1/$2/$3 notation.

CREATE OR REPLACE FUNCTION foo_func(timestamp,timestamp,code)
 RETURNS SETOF foo AS
BODY$
    SELECT
    TRH.ID,
    TRH.data1,
    TRH.data2,
    FROM D
    INNER JOIN  TS
         ON TS.id = D.id
    inner join TRH
         on ts.id = trh.id
    WHERE D.start_timestamp BETWEEN $1 AND $2
    And D.code IN ($3)
$BODY$
LANGUAGE 'sql' IMMUTABLE STRICT;


But If I were to use ALIASINg, I get an error

eg: DECLARE
  DECLARE
    fromdate ALIAS for $1;
    todate ALIAS for $2;
    code ALIAS for $3;


ERROR:  syntax error at or near "ALIAS"
LINE 5:     fromdate ALIAS for $1;
              ^