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#pragma once
#include <Core/NamesAndTypes.h>
#include <Analyzer/IQueryTreeNode.h>
#include <DataTypes/DataTypeNullable.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
/** Column node represents column in query tree.
* Column node can have weak pointer to its column source.
* Column source can be table expression, lambda, subquery.
*
* For table ALIAS columns. Column node must contain expression.
* For ARRAY JOIN join expression column. Column node must contain expression.
*
* During query analysis pass identifier node is resolved into column. See IdentifierNode.h.
*
* Examples:
* SELECT id FROM test_table. id is identifier that must be resolved to column node during query analysis pass.
* SELECT lambda(x -> x + 1, [1,2,3]). x is identifier inside lambda that must be resolved to column node during query analysis pass.
*
* Column node is initialized with column name, type and column source weak pointer.
* In case of ALIAS column node is initialized with column name, type, alias expression and column source weak pointer.
*/
class ColumnNode;
using ColumnNodePtr = std::shared_ptr<ColumnNode>;
class ColumnNode final : public IQueryTreeNode
{
public:
/// Construct column node with column name, type, column expression and column source weak pointer
ColumnNode(NameAndTypePair column_, QueryTreeNodePtr expression_node_, QueryTreeNodeWeakPtr column_source_);
/// Construct column node with column name, type and column source weak pointer
ColumnNode(NameAndTypePair column_, QueryTreeNodeWeakPtr column_source_);
/// Get column
const NameAndTypePair & getColumn() const
{
return column;
}
/// Get column name
const String & getColumnName() const
{
return column.name;
}
/// Get column type
const DataTypePtr & getColumnType() const
{
return column.type;
}
/// Set column type
void setColumnType(DataTypePtr column_type)
{
column.type = std::move(column_type);
}
/// Returns true if column node has expression, false otherwise
bool hasExpression() const
{
return children[expression_child_index] != nullptr;
}
/// Get column node expression node
const QueryTreeNodePtr & getExpression() const
{
return children[expression_child_index];
}
/// Get column node expression node
QueryTreeNodePtr & getExpression()
{
return children[expression_child_index];
}
/// Get column node expression node, if there are no expression node exception is thrown
QueryTreeNodePtr & getExpressionOrThrow()
{
if (!children[expression_child_index])
throw Exception(ErrorCodes::LOGICAL_ERROR, "Column expression is not initialized");
return children[expression_child_index];
}
/// Set column node expression node
void setExpression(QueryTreeNodePtr expression_value)
{
children[expression_child_index] = std::move(expression_value);
}
/** Get column source.
* If column source is not valid logical exception is thrown.
*/
QueryTreeNodePtr getColumnSource() const;
/** Get column source.
* If column source is not valid null is returned.
*/
QueryTreeNodePtr getColumnSourceOrNull() const;
QueryTreeNodeType getNodeType() const override
{
return QueryTreeNodeType::COLUMN;
}
DataTypePtr getResultType() const override
{
return column.type;
}
void convertToNullable() override
{
column.type = makeNullableSafe(column.type);
}
void dumpTreeImpl(WriteBuffer & buffer, FormatState & state, size_t indent) const override;
protected:
bool isEqualImpl(const IQueryTreeNode & rhs) const override;
void updateTreeHashImpl(HashState & hash_state) const override;
QueryTreeNodePtr cloneImpl() const override;
ASTPtr toASTImpl(const ConvertToASTOptions & options) const override;
private:
const QueryTreeNodeWeakPtr & getSourceWeakPointer() const
{
return weak_pointers[source_weak_pointer_index];
}
QueryTreeNodeWeakPtr & getSourceWeakPointer()
{
return weak_pointers[source_weak_pointer_index];
}
NameAndTypePair column;
static constexpr size_t expression_child_index = 0;
static constexpr size_t children_size = expression_child_index + 1;
static constexpr size_t source_weak_pointer_index = 0;
static constexpr size_t weak_pointers_size = source_weak_pointer_index + 1;
};
}
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