Function get_dqa_expr

src/backend/utils/adt/ruleutils.c:10144–10177

}

static void
get_dqa_expr(DQAExpr *dqa_expr,deparse_context *context)
{
	int id = -1;
	StringInfo	buf = context->buf;
	Bitmapset *bm = dqa_expr->agg_args_id_bms;
	deparse_namespace *dnps = (deparse_namespace *) linitial(context->namespaces);

	resetStringInfo(buf);
	appendStringInfoChar(buf, '(');
	while ((id = bms_next_member(bm, id)) >= 0)
	{
		TargetEntry *te = get_sortgroupref_tle((Index)id, dnps->plan->targetlist);
		char	   *exprstr;

		if (!te)
			elog(ERROR, "no tlist entry for sort key: %d", id);
		/* Deparse the expression, showing any top-level cast */
		exprstr = deparse_expression((Node *) te->expr, context->namespaces,
		                             context->varprefix, true);

		appendStringInfoString(buf, exprstr);
		appendStringInfoChar(buf, ',');
	}
	buf->data[buf->len - 1] = ')';

	if (dqa_expr->agg_filter != NULL)
	{
		appendStringInfoString(buf, " FILTER (WHERE ");
		get_rule_expr((Node *) dqa_expr->agg_filter, context, false);
		appendStringInfoChar(buf, ')');
	}

}

/*
 * get_agg_expr			- Parse back an Aggref node