CREATE OR REPLACE FUNCTION pruebas(varchar, varchar, integer)
RETURNS void
AS
$delimiter$
INSERT INTO documentos(descripcion) SELECT $1
WHERE NOT EXISTS ( SELECT id FROM documentos WHERE descripcion = $1 );
INSERT INTO personal ( nombre, idtipodocumento, numdoc )
SELECT $2, ( SELECT id FROM documentos WHERE descripcion = $1 ), $3;
$delimiter$
LANGUAGE SQL;