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Allow casting Tuple as Map.

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SELECT CAST(([1, 2, 3], ['1', '2', 'foo']), 'Map(UInt8, String)') AS map
This commit is contained in:
Vasily Nemkov 2020-10-26 21:20:45 +03:00
parent 483be134b2
commit e0d85ffd1d
1 changed files with 21 additions and 0 deletions
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21
src/Functions/FunctionsConversion.h
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@ -2164,6 +2164,27 @@ private:
WrapperType createMapWrapper(const DataTypePtr & from_type_untyped, const DataTypeMap * to_type) const
{
if (const auto from_tuple = checkAndGetDataType<DataTypeTuple>(from_type_untyped.get()))
{
if (from_tuple->getElements().size() != to_type->getElements().size())
throw Exception{"CAST AS Map from tuple with not enough elements.\n"
"Left type: " + from_tuple->getName() + ", right type: " + to_type->getName(), ErrorCodes::TYPE_MISMATCH};
return []
(ColumnsWithTypeAndName & arguments, const DataTypePtr &, const ColumnNullable * /*nullable_source*/, size_t /*input_rows_count*/)
{
const auto col = arguments.front().column.get();
const auto & column_tuple = typeid_cast<const ColumnTuple &>(*col);
Columns converted_columns(2);
converted_columns[0] = column_tuple.getColumns()[0];
converted_columns[1] = column_tuple.getColumns()[1];
return ColumnMap::create(converted_columns);
};
}
const auto from_type = checkAndGetDataType<DataTypeMap>(from_type_untyped.get());
if (!from_type)
throw Exception{"CAST AS Map can only be performed between map types.\nLeft type: "