Function exprIsNullConstant

src/backend/parser/parse_expr.c:882–893

Test whether an a_expr is a plain NULL constant or not */

/* Test whether an a_expr is a plain NULL constant or not */
static bool
exprIsNullConstant(Node *arg)
{
	if (arg && IsA(arg, A_Const))
	{
		A_Const    *con = (A_Const *) arg;

		if (con->val.type == T_Null)
			return true;
	}
	return false;
}

static Node *
transformAExprOp(ParseState *pstate, A_Expr *a)