Re: PREPARE dynamic SQL in plpgsql

On Fri, Mar 11, 2016 at 4:45 PM, Koichi Suzuki <koichi(dot)szk(at)gmail(dot)com> wrote:

> Hi,
>
> Does someone know how to prepare a synamic SQL statement in plpgsql?
>
> All the examples, PG documents describe only about preparing static SQL
> statement.
>
>
You might want to rephrase the question. From the pl/pgsql documentation:

"Note: The PL/pgSQL EXECUTE statement is not related to the EXECUTE SQL
statement supported by the PostgreSQL server. The server's EXECUTE
statement cannot be used directly within PL/pgSQL functions (and is not
needed)."

http://www.postgresql.org/docs/9.5/interactive/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN

So even if you could SQL-PREPARE you wouldn't be able to execute it.

The linked section describes how to construct and execute dynamic queries
in pl/pgsql. The short answer is you create variable of type text and then
EXECUTE it.

stmt := format('SELECT * FROM %i', in_tbl_name);
EXECUTE stmt [...]

David J.