Function PASS1_sort

src/dsql/pass1.cpp:2320–2424

Process ORDER BY list, which may contain an ordinal or alias which references the select list.

// Process ORDER BY list, which may contain an ordinal or alias which references the select list.
ValueListNode* PASS1_sort(DsqlCompilerScratch* dsqlScratch, ValueListNode* input, ValueListNode* selectList)
{
	DEV_BLKCHK(dsqlScratch, dsql_type_req);
	DEV_BLKCHK(input, dsql_type_nod);
	DEV_BLKCHK(selectList, dsql_type_nod);

	thread_db* tdbb = JRD_get_thread_data();
	MemoryPool& pool = *tdbb->getDefaultPool();

	if (!input)
	{
		ERRD_post(Arg::Gds(isc_sqlerr) << Arg::Num(-104) <<
				  Arg::Gds(isc_dsql_command_err) <<
				  // invalid ORDER BY clause
				  Arg::Gds(isc_order_by_err));
	}

	if (input->items.getCount() > MAX_SORT_ITEMS)
	{
		ERRD_post(Arg::Gds(isc_sqlerr) << Arg::Num(-104) <<
				  Arg::Gds(isc_dsql_command_err) <<
				  Arg::Gds(isc_order_by_err) <<
				  // invalid ORDER BY clause, cannot sort on more than 255 items
				  Arg::Gds(isc_dsql_max_sort_items));
	}

	// Node is simply to be rebuilt -- just recurse merrily

	NestConst<ValueListNode> node = FB_NEW_POOL(pool) ValueListNode(pool, input->items.getCount());
	NestConst<ValueExprNode>* ptr2 = node->items.begin();

	for (FB_SIZE_T sortloop = 0; sortloop < input->items.getCount(); ++sortloop)
	{
		DEV_BLKCHK(input->items[sortloop], dsql_type_nod);
		NestConst<OrderNode> node1 = nodeAs<OrderNode>(input->items[sortloop]);
		if (!node1)
		{
			ERRD_post(Arg::Gds(isc_sqlerr) << Arg::Num(-104) <<
					  Arg::Gds(isc_dsql_command_err) <<
					  // invalid ORDER BY clause
					  Arg::Gds(isc_order_by_err));
		}

		// get node of value to be ordered by
		NestConst<ValueExprNode> orderValue = node1->value;

		NestConst<CollateNode> collateNode = nodeAs<CollateNode>(orderValue);

		if (collateNode)
		{
			// substitute CollateNode with its argument (real value)
			orderValue = collateNode->arg;
		}

		FieldNode* field;
		LiteralNode* literal;

		if ((field = nodeAs<FieldNode>(orderValue)))