I think this will be more efficient:

* find the min position of the columnsToDrop
* sort the columnsToDrop by position using same comparator as you have above
* int columnsToDropIndex = 0;
* loop over all the columns starting at columnsToDrop[columnsToDropIndex++].getPosition() + 1
*    if (column == columnsToDrop[columnsToDropIndex] ) { columnsToDropIndex++; }
*    same logic as you have now, except colUpdate.setInt(5, column.getPosition() + columnsToDropIndex);