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analyzer - fix combine logic for limit expression and limit setting

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This commit is contained in:
Yakov Olkhovskiy 2023-03-08 05:40:10 +00:00
parent 673147e6dd
commit 7966c114bd
1 changed files with 44 additions and 9 deletions
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53
src/Analyzer/QueryTreeBuilder.cpp
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@ -355,21 +355,56 @@ QueryTreeNodePtr QueryTreeBuilder::buildSelectExpression(const ASTPtr & select_q
if (select_limit_by)
current_query_tree->getLimitByNode() = buildExpressionList(select_limit_by, current_context);
/// Combine limit expression with limit setting
/// Combine limit expression with limit and offset settings into final limit expression
/// select_limit - limit expression
/// limit - limit setting
/// offset - offset setting
///
/// if select_limit
/// -- if offset >= select_limit (expr 0)
/// then (0) (0 rows)
/// -- else if limit > 0 (expr 1)
/// then min(select_limit - offset, limit) (expr 2)
/// -- else
/// then (select_limit - offset) (expr 3)
/// else if limit > 0
/// then limit
///
/// offset = offset + of_expr
auto select_limit = select_query_typed.limitLength();
if (select_limit && limit)
if (select_limit)
{
auto function_node = std::make_shared<FunctionNode>("least");
function_node->getArguments().getNodes().push_back(buildExpression(select_limit, current_context));
function_node->getArguments().getNodes().push_back(std::make_shared<ConstantNode>(limit));
/// expr 3
auto expr_3 = std::make_shared<FunctionNode>("minus");
expr_3->getArguments().getNodes().push_back(buildExpression(select_limit, current_context));
expr_3->getArguments().getNodes().push_back(std::make_shared<ConstantNode>(offset));
/// expr 2
auto expr_2 = std::make_shared<FunctionNode>("least");
expr_2->getArguments().getNodes().push_back(expr_3->clone());
expr_2->getArguments().getNodes().push_back(std::make_shared<ConstantNode>(limit));
/// expr 0
auto expr_0 = std::make_shared<FunctionNode>("greaterOrEquals");
expr_0->getArguments().getNodes().push_back(std::make_shared<ConstantNode>(offset));
expr_0->getArguments().getNodes().push_back(buildExpression(select_limit, current_context));
/// expr 1
auto expr_1 = std::make_shared<ConstantNode>(limit > 0);
auto function_node = std::make_shared<FunctionNode>("multiIf");
function_node->getArguments().getNodes().push_back(expr_0);
function_node->getArguments().getNodes().push_back(std::make_shared<ConstantNode>(0));
function_node->getArguments().getNodes().push_back(expr_1);
function_node->getArguments().getNodes().push_back(expr_2);
function_node->getArguments().getNodes().push_back(expr_3);
current_query_tree->getLimit() = std::move(function_node);
}
else if (limit)
else if (limit > 0)
current_query_tree->getLimit() = std::make_shared<ConstantNode>(limit);
else if (select_limit)
current_query_tree->getLimit() = buildExpression(select_limit, current_context);
/// Combine offset expression with offset setting
/// Combine offset expression with offset setting into final offset expression
auto select_offset = select_query_typed.limitOffset();
if (select_offset && offset)
{