Not ble to drop a column from columnstore table

ALTER TABLE table1 drop column col1 ;

it is throwing below error Error Code: 1890. This version of MemSQL cannot perform an offline ALTER TABLE on a COLUMN STORE table. The requested ALTER TABLE cannot be performed online because it drops an index from a columnstore table.

This means the column is in an index. The index must be dropped before the column can be dropped. You can see what the index name is by running SHOW CREATE TABLE table1. The index can then be dropped by running ALTER TABLE table1 DROP INDEX index_name