Selecting check boxes on found group, not replace field contents but add to field contents
I have added a new check box to my field, and there are 5000 records out of 12000 that need this box checked. The records in this field already have other check boxes ticked.
If the field was empty I would use replace field contents to check the boxes on the 5000, however, I can't do this as there is already data checked that I want to keep.
How do I do this? Btw, I tried on table view to hold down shift and select the column before clicking the box, like excel, but this didn't work.