Method convertNeqAllToNotAny

src/dsql/BoolNodes.cpp:2081–2164

Try to convert nodes of expression: select ... from where not in (select from ) (and its variants that uses the same BLR: {NOT (a = ANY b)} and {a <> ALL b}) to: select ... from where not ((x is null and exists (select 1 from )) or exists (select from where = or is null)) Because the second form can use indexes. Returns NULL when not converted, and a

// Because the second form can use indexes.
// Returns NULL when not converted, and a new node to be processed when converted.
BoolExprNode* RseBoolNode::convertNeqAllToNotAny(thread_db* tdbb, CompilerScratch* csb)
{
	SET_TDBB(tdbb);

	fb_assert(blrOp == blr_ansi_all);

	RseNode* outerRse = rse;	// blr_ansi_all rse
	ComparativeBoolNode* outerRseNeq;

	if (!outerRse ||
		outerRse->getType() != RseNode::TYPE ||		// Reduntant test?
		outerRse->rse_relations.getCount() != 1 ||
		!outerRse->rse_boolean ||
		!(outerRseNeq = nodeAs<ComparativeBoolNode>(outerRse->rse_boolean)) ||
		outerRseNeq->blrOp != blr_neq)
	{
		return NULL;
	}

	RseNode* innerRse = static_cast<RseNode*>(outerRse->rse_relations[0].getObject());	// user rse

	// If the rse is different than we expected, do nothing. Do nothing also if it uses FIRST or
	// SKIP, as we can't inject booleans there without changing the behavior.
	if (!innerRse || innerRse->getType() != RseNode::TYPE || innerRse->rse_first || innerRse->rse_skip)
		return NULL;

	NotBoolNode* newNode = FB_NEW_POOL(csb->csb_pool) NotBoolNode(csb->csb_pool);

	BinaryBoolNode* orNode = FB_NEW_POOL(csb->csb_pool) BinaryBoolNode(csb->csb_pool, blr_or);

	newNode->arg = orNode;

	BinaryBoolNode* andNode = FB_NEW_POOL(csb->csb_pool) BinaryBoolNode(csb->csb_pool, blr_and);

	orNode->arg1 = andNode;

	MissingBoolNode* missNode = FB_NEW_POOL(csb->csb_pool) MissingBoolNode(csb->csb_pool);
	missNode->arg = outerRseNeq->arg1;

	andNode->arg1 = missNode;

	RseNode* newInnerRse1 = innerRse->clone(csb->csb_pool);
	newInnerRse1->flags |= RseNode::FLAG_SUB_QUERY;

	RseBoolNode* rseBoolNode = FB_NEW_POOL(csb->csb_pool) RseBoolNode(csb->csb_pool, blr_any);
	rseBoolNode->rse = newInnerRse1;
	rseBoolNode->ownSavepoint = this->ownSavepoint;

	andNode->arg2 = rseBoolNode;

	RseNode* newInnerRse2 = innerRse->clone(csb->csb_pool);
	newInnerRse2->flags |= RseNode::FLAG_SUB_QUERY;

	rseBoolNode = FB_NEW_POOL(csb->csb_pool) RseBoolNode(csb->csb_pool, blr_any);
	rseBoolNode->rse = newInnerRse2;
	rseBoolNode->ownSavepoint = this->ownSavepoint;

	orNode->arg2 = rseBoolNode;