Join Field Not Working

[LeviCecil]

I've been having this problem lately, where the join field tool won't work in Pro 2.6 or 2.7, or Python 3.7.9. I'll try to join on two fields that I know are identical, and it will say "WARNING 003237: Join had no matches." Is anyone else having this trouble? When I run the same script in Python 2.7, the fields join. This happens whether I'm trying to join a csv to a feature class, fc to fc, or a gdb table to fc. 

[SGuiryVR]

I get the same issue, even though I performed calculate field based on a .csv table based on an ID # value, then when I remove join and try to join again based on the calculated field it says the join had no matches

[Spatialelement]

Has this issue been resolved? I'm currently trying to perform a very simple join in ArcGIS Pro V2.9.0 and am getting the same "WARNING 003237: Join had no matches". This warning ID doesn't seem to appear in any help documentation other than this thread.

I've checked the raw data for any blank values etc. I've indexed my join fields. I've converted my incoming CSV to a table stored in my projects default geodatabase. Nothing seems to be working. 

[skyhook]

also suffering from this bug. same as described above.  taken all previously mentioned steps & attempting to join 2 file geodatabase tables. Shortly before tool finishes it's run I see "0 matches" & i get NULL output. However, history & processing details just show operation succeeded with no warnings or errors.  This is a huge disruption in workflow.  reminds me of the common joke:  funny how arcmap is more useful than ever before now that it's end-of-life & not updated any longer. 

[shan_sarkar]

That is definitely weird, however can you check if there are any extra spaces before or at the end of the fields you are trying to join. If there are extra spaces in the values then arcgis will fail to see them as the same or identical values as it compares the values character by character.

[ArsenBeglaryan]

***UPDATE***

I have done some tests today shortening paths etc. and that was not the issue. The cause of this was one row manually selected and forgotten in my 1200 row input table. For that reason the Join Field GP tool was returning no matches. It started working properly as soon as I unselected the row in the input table, no queries were applied. Working on ArcGIS Pro 2.9.1


Any updates on the issue?
It is already becoming a bit "not funny" at all. Having the same issue on 2.9, losing tons of time having to perform this simple task on an ArcMap, QGIS or other tools. 
It works one time and keeps on failing other times in ArcGIS Pro with same parameters, either Warning 003237 or tool finding 1 match only.
I have no nulls, spaces etc., having a "table to table" table in the default GDB, that already worked one time and kept on failing other times with same parameters. 

Only other potential solution I am thinking of, is the long path issue on Windows machines. I had this type of weird errors in other GP tools that got solved shortening the names and paths etc., but did not try in this case.

[LeviCecil]

Here's a fun new wrinkle in Pro 2.9.1. Lately I've been successfully joining from Excel sheets. The other day I added new fields to a Sites points dataset and calculated values from an Excel sheet using the Site ID field as the join. I found out this morning that the Site ID field in around 45 of our sites was deleted during this process. They were nulls. This messed up the functionality of our facilities dashboard app. I had to go in and add the Site IDs back in. This is a real problem. 

[JosephAlberts]

I was just running into this problem myself on Pro 2.9.2.

Basic steps were Table to Geodatabase from CSVs prepared for me, attempt join from a hosted feature layer added to the map to the new table. I was joining from the GlobalID of the hosted feature layer (type: GlobalID) to the GlobalID in the table (type: string, length: 255).

If I reversed the join (i.e, table to hosted feature layer, same join field), everything was fine.

It seems like my problem, in this case, was that I had a definition query applied to the hosted feature layer. When I turned it off, I was able to get a correct match count when validating the join from the hosted feature layer to the table.

That's definitely not the behavior I would expect though.

[ColinHLang]

I have been seeing this recently in ArcGIS Pro 2.9.7.  Two tables will not join, especially when the join field is a text field.  I can visibly see the matches, but the software can't find them.  No leading or trailing zeros or spaces.  Some null records, so that is one thing I'll have to investigate, but I've also found I have better results often after I index the field on both sides of the join.  Why it would fail without an index and succeed with it is vexing me.  I would expect it to just take longer, not fail completely.  Joins definitely work a lot better in ArcMap than they do in Pro, and that should not be the case.  This is some of the most basic functionality of GIS.  

[Kalgul]

I have aged about 10 years in the past few workdays, spending about 15 man-hours trying to get past this ONE problem which has completely stopped my workflow in a career-defining project.  Selecting by attribute confirms the matching entries for a 1:M join, but it just will not join, no matter what I do.  I have the shapefile, I have the csv, I have both of them exported to a geodatabase, and nothing I do has gotten past the cursed 'WARNING 003237: Join had no matches.' error.

[LeviCecil]

If you have access to the Data Interoperability extension for Pro, I would highly recommending using it for joins and attribute management in general. It's basically a lite version of Safe FME software, which is basically a really advanced version of model builder. It does these sorts of tasks so much better than ArcGIS Pro. I'm moving some of my processes out of Python/ArcPy into FME and it's very effective.