mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-29 19:12:03 +00:00
239 lines
12 KiB
C++
239 lines
12 KiB
C++
#include <Functions/IFunction.h>
|
|
#include <Functions/FunctionFactory.h>
|
|
#include <Functions/FunctionHelpers.h>
|
|
#include <DataTypes/IDataType.h>
|
|
#include <DataTypes/DataTypeArray.h>
|
|
#include <DataTypes/DataTypeVariant.h>
|
|
#include <DataTypes/DataTypeFactory.h>
|
|
#include <Columns/ColumnArray.h>
|
|
#include <Columns/ColumnString.h>
|
|
#include <Columns/ColumnVariant.h>
|
|
#include <Columns/ColumnNullable.h>
|
|
#include <Columns/ColumnLowCardinality.h>
|
|
#include <Common/assert_cast.h>
|
|
#include <memory>
|
|
|
|
|
|
namespace DB
|
|
{
|
|
|
|
namespace ErrorCodes
|
|
{
|
|
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
|
|
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
|
|
}
|
|
|
|
namespace
|
|
{
|
|
|
|
/** Extract element of Variant by variant type name.
|
|
* Also the function looks through Arrays: you can get Array of Variant elements from Array of Variants.
|
|
*/
|
|
class FunctionVariantElement : public IFunction
|
|
{
|
|
public:
|
|
static constexpr auto name = "variantElement";
|
|
|
|
static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionVariantElement>(); }
|
|
String getName() const override { return name; }
|
|
bool isVariadic() const override { return true; }
|
|
size_t getNumberOfArguments() const override { return 0; }
|
|
bool useDefaultImplementationForConstants() const override { return true; }
|
|
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {1}; }
|
|
bool useDefaultImplementationForNulls() const override { return false; }
|
|
bool useDefaultImplementationForLowCardinalityColumns() const override { return false; }
|
|
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return true; }
|
|
|
|
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
|
|
{
|
|
const size_t number_of_arguments = arguments.size();
|
|
|
|
if (number_of_arguments < 2 || number_of_arguments > 3)
|
|
throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH,
|
|
"Number of arguments for function {} doesn't match: passed {}, should be 2 or 3",
|
|
getName(), number_of_arguments);
|
|
|
|
size_t count_arrays = 0;
|
|
const IDataType * input_type = arguments[0].type.get();
|
|
while (const DataTypeArray * array = checkAndGetDataType<DataTypeArray>(input_type))
|
|
{
|
|
input_type = array->getNestedType().get();
|
|
++count_arrays;
|
|
}
|
|
|
|
const DataTypeVariant * variant_type = checkAndGetDataType<DataTypeVariant>(input_type);
|
|
if (!variant_type)
|
|
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
|
|
"First argument for function {} must be Variant or Array of Variant. Actual {}",
|
|
getName(),
|
|
arguments[0].type->getName());
|
|
|
|
std::optional<size_t> variant_global_discr = getVariantGlobalDiscriminator(arguments[1].column, *variant_type, number_of_arguments);
|
|
if (variant_global_discr.has_value())
|
|
{
|
|
DataTypePtr return_type = makeNullableOrLowCardinalityNullableSafe(variant_type->getVariant(variant_global_discr.value()));
|
|
|
|
for (; count_arrays; --count_arrays)
|
|
return_type = std::make_shared<DataTypeArray>(return_type);
|
|
|
|
return return_type;
|
|
}
|
|
else
|
|
return arguments[2].type;
|
|
}
|
|
|
|
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
|
|
{
|
|
const auto & input_arg = arguments[0];
|
|
const IDataType * input_type = input_arg.type.get();
|
|
const IColumn * input_col = input_arg.column.get();
|
|
|
|
bool input_arg_is_const = false;
|
|
if (typeid_cast<const ColumnConst *>(input_col))
|
|
{
|
|
input_col = assert_cast<const ColumnConst *>(input_col)->getDataColumnPtr().get();
|
|
input_arg_is_const = true;
|
|
}
|
|
|
|
Columns array_offsets;
|
|
while (const DataTypeArray * array_type = checkAndGetDataType<DataTypeArray>(input_type))
|
|
{
|
|
const ColumnArray * array_col = assert_cast<const ColumnArray *>(input_col);
|
|
|
|
input_type = array_type->getNestedType().get();
|
|
input_col = &array_col->getData();
|
|
array_offsets.push_back(array_col->getOffsetsPtr());
|
|
}
|
|
|
|
const DataTypeVariant * input_type_as_variant = checkAndGetDataType<DataTypeVariant>(input_type);
|
|
const ColumnVariant * input_col_as_variant = checkAndGetColumn<ColumnVariant>(input_col);
|
|
if (!input_type_as_variant || !input_col_as_variant)
|
|
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
|
|
"First argument for function {} must be Variant or array of Variants. Actual {}", getName(), input_arg.type->getName());
|
|
|
|
std::optional<size_t> variant_global_discr = getVariantGlobalDiscriminator(arguments[1].column, *input_type_as_variant, arguments.size());
|
|
|
|
if (!variant_global_discr.has_value())
|
|
return arguments[2].column;
|
|
|
|
const auto & variant_type = input_type_as_variant->getVariant(*variant_global_discr);
|
|
const auto & variant_column = input_col_as_variant->getVariantPtrByGlobalDiscriminator(*variant_global_discr);
|
|
|
|
/// If Variant has only NULLs or our variant doesn't have any real values,
|
|
/// just create column with default values and create null mask with 1.
|
|
if (input_col_as_variant->hasOnlyNulls() || variant_column->empty())
|
|
{
|
|
auto res = variant_type->createColumn();
|
|
|
|
if (variant_type->lowCardinality())
|
|
assert_cast<ColumnLowCardinality &>(*res).nestedToNullable();
|
|
|
|
res->insertManyDefaults(input_col_as_variant->size());
|
|
if (!variant_type->canBeInsideNullable())
|
|
return wrapInArraysAndConstIfNeeded(std::move(res), array_offsets, input_arg_is_const, input_rows_count);
|
|
|
|
auto null_map = ColumnUInt8::create();
|
|
auto & null_map_data = null_map->getData();
|
|
null_map_data.resize_fill(input_col_as_variant->size(), 1);
|
|
return wrapInArraysAndConstIfNeeded(ColumnNullable::create(std::move(res), std::move(null_map)), array_offsets, input_arg_is_const, input_rows_count);
|
|
}
|
|
|
|
/// If we extract single non-empty column and have no NULLs, then just return this variant.
|
|
if (auto non_empty_local_discr = input_col_as_variant->getLocalDiscriminatorOfOneNoneEmptyVariantNoNulls())
|
|
{
|
|
/// If we were trying to extract some other variant,
|
|
/// it would be empty and we would already processed this case above.
|
|
chassert(input_col_as_variant->globalDiscriminatorByLocal(*non_empty_local_discr) == variant_global_discr);
|
|
return wrapInArraysAndConstIfNeeded(makeNullableOrLowCardinalityNullableSafe(variant_column), array_offsets, input_arg_is_const, input_rows_count);
|
|
}
|
|
|
|
/// In general case we should calculate null-mask for variant
|
|
/// according to the discriminators column and expand
|
|
/// variant column by this mask to get a full column (with default values on NULLs)
|
|
const auto & local_discriminators = input_col_as_variant->getLocalDiscriminators();
|
|
auto null_map = ColumnUInt8::create();
|
|
auto & null_map_data = null_map->getData();
|
|
null_map_data.reserve(local_discriminators.size());
|
|
auto variant_local_discr = input_col_as_variant->localDiscriminatorByGlobal(*variant_global_discr);
|
|
for (auto local_discr : local_discriminators)
|
|
null_map_data.push_back(local_discr != variant_local_discr);
|
|
|
|
auto expanded_variant_column = IColumn::mutate(variant_column);
|
|
if (variant_type->lowCardinality())
|
|
expanded_variant_column = assert_cast<ColumnLowCardinality &>(*expanded_variant_column).cloneNullable();
|
|
expanded_variant_column->expand(null_map_data, /*inverted = */ true);
|
|
if (variant_type->canBeInsideNullable())
|
|
return wrapInArraysAndConstIfNeeded(ColumnNullable::create(std::move(expanded_variant_column), std::move(null_map)), array_offsets, input_arg_is_const, input_rows_count);
|
|
return wrapInArraysAndConstIfNeeded(std::move(expanded_variant_column), array_offsets, input_arg_is_const, input_rows_count);
|
|
}
|
|
private:
|
|
std::optional<size_t> getVariantGlobalDiscriminator(const ColumnPtr & index_column, const DataTypeVariant & variant_type, size_t argument_size) const
|
|
{
|
|
const auto * name_col = checkAndGetColumnConst<ColumnString>(index_column.get());
|
|
if (!name_col)
|
|
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
|
|
"Second argument to {} with Variant argument must be a constant String",
|
|
getName());
|
|
|
|
String variant_element_name = name_col->getValue<String>();
|
|
auto variant_element_type = DataTypeFactory::instance().tryGet(variant_element_name);
|
|
if (variant_element_type)
|
|
{
|
|
const auto & variants = variant_type.getVariants();
|
|
for (size_t i = 0; i != variants.size(); ++i)
|
|
{
|
|
if (variants[i]->getName() == variant_element_type->getName())
|
|
return i;
|
|
}
|
|
}
|
|
|
|
if (argument_size == 2)
|
|
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "{} doesn't contain variant with type {}", variant_type.getName(), variant_element_name);
|
|
return std::nullopt;
|
|
}
|
|
|
|
ColumnPtr wrapInArraysAndConstIfNeeded(ColumnPtr res, const Columns & array_offsets, bool input_arg_is_const, size_t input_rows_count) const
|
|
{
|
|
for (auto it = array_offsets.rbegin(); it != array_offsets.rend(); ++it)
|
|
res = ColumnArray::create(res, *it);
|
|
|
|
if (input_arg_is_const)
|
|
res = ColumnConst::create(res, input_rows_count);
|
|
|
|
return res;
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
REGISTER_FUNCTION(VariantElement)
|
|
{
|
|
factory.registerFunction<FunctionVariantElement>(FunctionDocumentation{
|
|
.description = R"(
|
|
Extracts a column with specified type from a `Variant` column.
|
|
)",
|
|
.syntax{"variantElement(variant, type_name, [, default_value])"},
|
|
.arguments{{
|
|
{"variant", "Variant column"},
|
|
{"type_name", "The name of the variant type to extract"},
|
|
{"default_value", "The default value that will be used if variant doesn't have variant with specified type. Can be any type. Optional"}}},
|
|
.examples{{{
|
|
"Example",
|
|
R"(
|
|
CREATE TABLE test (v Variant(UInt64, String, Array(UInt64))) ENGINE = Memory;
|
|
INSERT INTO test VALUES (NULL), (42), ('Hello, World!'), ([1, 2, 3]);
|
|
SELECT v, variantElement(v, 'String'), variantElement(v, 'UInt64'), variantElement(v, 'Array(UInt64)') FROM test;)",
|
|
R"(
|
|
┌─v─────────────┬─variantElement(v, 'String')─┬─variantElement(v, 'UInt64')─┬─variantElement(v, 'Array(UInt64)')─┐
|
|
│ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ [] │
|
|
│ 42 │ ᴺᵁᴸᴸ │ 42 │ [] │
|
|
│ Hello, World! │ Hello, World! │ ᴺᵁᴸᴸ │ [] │
|
|
│ [1,2,3] │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ [1,2,3] │
|
|
└───────────────┴─────────────────────────────┴─────────────────────────────┴────────────────────────────────────┘
|
|
)"}}},
|
|
.categories{"Variant"},
|
|
});
|
|
}
|
|
|
|
}
|