1#include <Columns/ColumnNullable.h>
2
3
4namespace DB
5{
6
7/** Replace Nullable key_columns to corresponding nested columns.
8 * In 'null_map' return a map of positions where at least one column was NULL.
9 * @returns ownership column of null_map.
10 */
11ColumnPtr extractNestedColumnsAndNullMap(ColumnRawPtrs & key_columns, ConstNullMapPtr & null_map);
12
13}
14