#27685
{
    if (col->lowCardinality())
    {
        
        assert(!col->canBeInsideNullable());
        const auto * col_as_lc = assert_cast<const ColumnLowCardinality *>(col.get());
        return {true, col_as_lc->nestedIsNullable()};
    }
    return {false, col->isNullable()};
}
}
namespace JoinCommon
{
void changeLowCardinalityInplace(ColumnWithTypeAndName & column)
{
    if (column.type->lowCardinality())
    {
        column.type = recursiveRemoveLowCardinality(column.type);
        column.column = column.column->convertToFullColumnIfLowCardinality();
    }
    else
    {
        column.type = std::make_shared<DataTypeLowCardinality>(column.type);
        MutableColumnPtr lc = column.type->createColumn();
        typeid_cast<ColumnLowCardinality &>(*lc).insertRangeFromFullColumn(*column.column, 0, column.column->size());
        column.column = std::move(lc);
    }
}
bool canBecomeNullable(const DataTypePtr & type)