One-to-many join, joining shapefile to an Excel by zipcode without spatial location

[LABenitez]

I need help. I am using ArcMap 10.7.1.

I am trying to do one to many join. There are multiple records per zip code in the excel file. 

But it's only doing one to one join. I tried to convert the excel to dBASE Table so it will have an OID or put the files into geodatabase, convert the Excel to CSV and still no luck. I not sure what I am doing wrong. 

Thanks!

[JoeBorgione · Accepted solution]

It's only doing a 1 to 1 join because ArcMap does not do 1 to Many joins; it stops joining after the first instance of the key field.  

Personally, I would avoid any database-like operation directly to a spreadsheet opting to the convert the spreadsheet to a file geodatabase table.  Once you've done that you can create a relate on the fly or create a relationship class in the fgdb (assuming your shapefile is really a feature class and not a true shape file).

[LABenitez]

My zip code is a polygon shapefile that I downloaded from Esri.