Formula to find duplicate values in one field.

I'm curious to know what requirements made you not be able to use two separate tables, because that seems to be the ideal situation.

You might be able to use that summary field in a checkbox formula field by first checking if the Job ID has a "." in it as a delimiter and then checking the summary field amount.

Maybe something like:
If
(
Contains(ToText[Job ID],".")=False and [Summary Field]="1",True
)

//Checking first to make sure the record isn't a sub job then checking to see how many records have the same beginning values

If you haven't already made something like this - you can make another ID field that identifies the main job by taking all the numbers left of the decimal point so that the main job and the sub job have the same summary ID so to speak. This id would be used in the summary field, so if there is 1 main job with 3 sub jobs, the summary field would return "4"

------------------------------
Jordan McAlister
------------------------------