JOIN empty columns

If I make a join and don't want any columns to be fetched I should be able to pass null or empty string. Now if You do this, query will look like You tried to get an column, without its name.

$select->from("B");
$select->join("A", "A.A_ID = B.B_A_ID", null);

SELECT "B".*, "A". AS "" FROM "B" INNER JOIN "A" ON "A"."A_ID" = "B"."B_A_ID"