ClickHouse/dbms/src/Interpreters/NullableUtils.h

#include <Columns/ColumnNullable.h>


namespace DB
{

/** Replace Nullable key_columns to corresponding nested columns.
  * In 'null_map' return a map of positions where at least one column was NULL.
  * @returns ownership column of null_map.
  */
ColumnPtr extractNestedColumnsAndNullMap(ColumnRawPtrs & key_columns, ConstNullMapPtr & null_map);

}