how to pass tablename to a function

Started by A L.over 11 years ago3 messagesgeneral
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#1A L.
e_toner@hotmail.com

Hi, All

I like to pass the tablename to function but not using execute clause, here is my script

CREATE OR REPLACE FUNCTION functions.pgsql_event_unpack_batch(IN
_tbl text, IN jobid bigint, IN jobtime timestamp with time zone, IN
startid bigint, IN stopid bigint)

RETURNS TABLE(events bigint, errors bigint[]) AS

$BODY$

BEGIN

RETURN QUERY

WITH

unpacking (raw_id, time, userid, eventtype, pagename, userhost, application, status, error)

AS (

select

id as raw_id,

(up).time,

(up).userid,

coalesce((up).eventtype, ''),

coalesce((up).pagename, ''),

(up).userhostaddress as userhost,

coalesce((up).application, ''),

(up).status,

(up).error

from(

select id,

functions.python_events_unpack(event_object) up

from _tbl

where id between startid and stopid

) a

where (up).userid is not NULL

)

I want to pass the _tbl to the select query integrated in the unpacking(), how can I make it?

thanks

Alec

#2Adrian Klaver
adrian.klaver@aklaver.com
In reply to: A L. (#1)
Re: how to pass tablename to a function

On 09/04/2014 04:42 PM, A L. wrote:

Hi, All

I like to pass the tablename to function but not using execute clause,
here is my script

CREATE OR REPLACE FUNCTION functions.pgsql_event_unpack_batch(IN _tbl
text, IN jobid bigint, IN jobtime timestamp with time zone, IN startid
bigint, IN stopid bigint)
RETURNS TABLE(events bigint, errors bigint[]) AS
$BODY$
BEGIN

RETURN QUERY
WITH
unpacking (raw_id, time, userid, eventtype, pagename, userhost,
application, status, error)
AS (
select
id as raw_id,
(up).time,
(up).userid,
coalesce((up).eventtype, ''),
coalesce((up).pagename, ''),
(up).userhostaddress as userhost,
coalesce((up).application, ''),
(up).status,
(up).error
from(
select id,
functions.python_events_unpack(event_object) up
from _tbl
where id between startid and stopid
) a
where (up).userid is not NULL
)

I want to pass the _tbl to the select query integrated in the
unpacking(), how can I make it?

Assuming you are using plpgsql, see here:

http://www.postgresql.org/docs/9.3/interactive/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN

or use a language like plpythonu.

thanks

Alec

--
Adrian Klaver
adrian.klaver@aklaver.com

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#3David G. Johnston
david.g.johnston@gmail.com
In reply to: A L. (#1)
Re: how to pass tablename to a function

alecinvan wrote

I like to pass the tablename to function but not using execute clause,
here is my script

[...]

I want to pass the _tbl to the select query integrated in the unpacking(),
how can I make it?

There is no way to perform a query with an unknown, at design time,
identifier without using EXECUTE.

The recommended way to do this is to use "format()" and dollar-quoting -
v9.1+ required:

v_qry := format(

$qry$
WITH [...]
SELECT id, func(...) FROM %I WHERE id [...]
$qry$

, _tbl

);

RETURN QUERY EXECUTE v_qry;

David J.

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