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Allow for function "tupleElement" to get an edge of Array of Tuple (preparation for natural support of Nested) [#CLICKHOUSE-2].

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This commit is contained in:
Alexey Milovidov 2017-12-24 12:56:30 +03:00
parent 0f51be4191
commit 82d429f7ed
3 changed files with 46 additions and 7 deletions
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49
dbms/src/Functions/FunctionsMiscellaneous.cpp
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@ -814,6 +814,7 @@ public:
/** Extract element of tuple by constant index or name. The operation is essentially free.
* Also the function looks through Arrays: you can get Array of tuple elements from Array of Tuples.
*/
class FunctionTupleElement : public IFunction
{
@ -847,22 +848,56 @@ public:
void getReturnTypeAndPrerequisitesImpl(
const ColumnsWithTypeAndName & arguments, DataTypePtr & out_return_type, ExpressionActions::Actions & /*out_prerequisites*/) override
{
const DataTypeTuple * tuple = checkAndGetDataType<DataTypeTuple>(arguments[0].type.get());
size_t count_arrays = 0;
const IDataType * tuple_col = arguments[0].type.get();
while (const DataTypeArray * array = checkAndGetDataType<DataTypeArray>(tuple_col))
{
tuple_col = array->getNestedType().get();
++count_arrays;
}
const DataTypeTuple * tuple = checkAndGetDataType<DataTypeTuple>(tuple_col);
if (!tuple)
throw Exception("First argument for function " + getName() + " must be tuple.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
throw Exception("First argument for function " + getName() + " must be tuple or array of tuple.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
size_t index = getElementNum(arguments[1].column, *tuple);
out_return_type = tuple->getElements()[index];
for (; count_arrays; --count_arrays)
out_return_type = std::make_shared<DataTypeArray>(out_return_type);
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
{
const ColumnTuple * tuple_col = typeid_cast<const ColumnTuple *>(block.getByPosition(arguments[0]).column.get());
if (!tuple_col)
throw Exception("First argument for function " + getName() + " must be tuple.", ErrorCodes::ILLEGAL_COLUMN);
Columns array_offsets;
size_t index = getElementNum(block.getByPosition(arguments[1]).column, typeid_cast<const DataTypeTuple &>(*block.getByPosition(arguments[0]).type));
block.getByPosition(result).column = tuple_col->getColumns()[index];
const auto & first_arg = block.getByPosition(arguments[0]);
const IDataType * tuple_type = first_arg.type.get();
const IColumn * tuple_col = first_arg.column.get();
while (const DataTypeArray * array_type = checkAndGetDataType<DataTypeArray>(tuple_type))
{
const ColumnArray * array_col = static_cast<const ColumnArray *>(tuple_col);
tuple_type = array_type->getNestedType().get();
tuple_col = &array_col->getData();
array_offsets.push_back(array_col->getOffsetsPtr());
}
const DataTypeTuple * tuple_type_concrete = checkAndGetDataType<DataTypeTuple>(tuple_type);
const ColumnTuple * tuple_col_concrete = checkAndGetColumn<ColumnTuple>(tuple_col);
if (!tuple_type_concrete || !tuple_col_concrete)
throw Exception("First argument for function " + getName() + " must be tuple or array of tuple.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
size_t index = getElementNum(block.getByPosition(arguments[1]).column, *tuple_type_concrete);
ColumnPtr res = tuple_col_concrete->getColumns()[index];
/// Wrap into Arrays
for (auto it = array_offsets.rbegin(); it != array_offsets.rend(); ++it)
res = ColumnArray::create(res, *it);
block.getByPosition(result).column = res;
}
private:

2
dbms/tests/queries/0_stateless/00548_slice_of_nested.reference Normal file
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@ -0,0 +1,2 @@
[(1,'Hello'),(2,'World')] [1,2] ['Hello','World']
[[(1,'Hello'),(2,'World')],[(3,'Goodbye')]] [[1,2],[3]] [['Hello','World'],['Goodbye']]

2
dbms/tests/queries/0_stateless/00548_slice_of_nested.sql Normal file
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@ -0,0 +1,2 @@
SELECT [(1, 'Hello'), (2, 'World')] AS nested, nested.1, nested.2;
SELECT [[(1, 'Hello'), (2, 'World')], [(3, 'Goodbye')]] AS nested, nested.1, nested.2;