When we get different columns's row ranges by column_delete_conditions, we should use union operation instead of intersection operation to get final get final row ranges.
The root cause is that we lost the relationship of the two delete conditions in same delete stmt.
Base data:
```
k1, k2
1, 2
1, 3
case 1:
delete from tbl where k1=1 and k2=2;
case 2:
delete from tbl where k1=1;
delete from tbl where k2=2;
```
We treat the above 2 cases as same, which is incorrect.
So we need to process every rowset of delete conditions separately.
9785e103ea