Delete from table where col is null;

这样写不行，删除不掉；

youdao

Delete a row from a table with 10 indexes, and DB2 must remove all index entries associated with the deleted rows.

如果从一个带有10个索引的表删除一行，DB 2必须删除与被删除的行关联的所有索引条目。

youdao

The simple answer is to delete the table from the database and, if necessary, create a replacement table.

简单的答案是从数据库中删除表。而且，如果必要，再创建一个替代表。

youdao