Having the relationship based on the dwg field is causing the results you are seeing. Filemaker is looking for an exact match. To get around this, a Cartesian join can be used. Using this along with a global field and filtering the portal based on the contents of the global will give the results you are looking for.
I believe you are absolutely correct on this. Can you elaborate on the calculation for the portal filtering. if I do "tbl_dwgs::dwg = gtbldwglookup::dwg" in the calculation it behaves the same way as if the tables were joined without the Cartesian method. I cannot seem to find a "like" operator, and wildcards do not appear to be working.
Which version of FileMaker are you using?
The first thing you can do is use the function Patterncount(). The filter calculation would be Patterncount(tbl_dwgs::dwg; gtbldwglookup::dwg)
A second method is to base the portal relationship off the global field you are filtering. The method would work as follows:
1. Add a ListOf summary field to your portal table. Make sure it gets a list of the primary keys of your portal table.
2. On your layout , the user enters criteria in the filter.
2. A script trigger (Likely onSave) performs a Find on the table defined in the portal.
3. Set your global field to the value stored in your ListOf summary field. This is a list of all of the primary keys in the found set you just obtained. This will trigger the relationship between the tables and show the found records.
The first method is the purer LIKE method as you can find phrases in the middle of words. FileMaker Finds searches start at the beginning of words, so you would not get the same results as a Patterncount. Additionally, the portal would not show any results until a value is entered in the global field. Your portal will show up empty to start.
I hope this helps.
Edit: I forgot to mention that ListOf is only available in 13 and 14. That is the reason I ask above.
I wish I could mark both as Best Answer! Thanks so much, it worked perfectly.