Last week, I refactored an update query into smaller queries looping and doing only 20 updates at a time because too many updates was taking more time than allo

Last week, I refactored an update query into smaller queries looping and doing only 20 updates at a time because too many updates was taking more time than allowed. It turns out that one query that happens is to remove a field of it isn't one of the query values. Well, if you split that list of query values into several disjoint sets, then it turns out that the field is removed in all records! Whoops.