Обсуждение: Table name as a variable in SELECT query

Hi,
please advise is possible in SELECT query use variable as a table name?

I would like to have  for example something like:

CREATE OR REPLACE FUNCTION test_name (tb varchar) RETURNS int AS  $$

DECLARE
                ......

BEGIN    SELECT * FROM $1;    ........

Will be grateful for any idea about.


Best regards           Andrey

Andrey Fokin <affox@myway.com> wrote:

> Hi,
> please advise is possible in SELECT query use variable as a table name?
> 
> I would like to have  for example something like:
> 
> CREATE OR REPLACE FUNCTION test_name (tb varchar) RETURNS int AS  $$
> 
> DECLARE 
> 
>                  ......
> 
> BEGIN
>         SELECT * FROM $1;
>         ........
> 
> Will be grateful for any idea about.

Yes, it is possible, with dynamic sql. You have to build a string that
contains your query, and then execute (it's a command in pl/pgsql) that
string. Read more:

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


Andreas
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