postgres de consulta dinámica

Aquí debe visitar el EXECUTE declaracion de plpgsql, which would do what you are trying to do - execute an SQL query string. You tagged lugar de trabajo dinámico, so this may be what you are looking for.

Only works inside plpgsql functions or DO statements (anonymous code blocks). La distinción entre EXECUTE y SQL-EXECUTE made clear in the fine manual:

Nota: 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).

If you want to return values from a dynamic SELECT query as your example indicates, you need to create a function. DO las declaraciones siempre regresan void. More about returning values from a function in the very fine manual.

Desde el fino manual:

sinopsis

EXECUTE name [ ( parameter [, ...] ) ]

Descripción

EXECUTE is used to execute a previously prepared statement.

So EXECUTE doesn't execute a string of SQL, it execute a prepared statement that is identified by a name and you need to prepare the statement separately using PREPARAR:

=> prepare stmt as select * from products;
=> execute stmt;
-- "select * from products" output goes here...