I have 2 fields in the same table which represent the same thing but they were unioned from 2 different data sets, lets call them A and B. Lets say there are 50 records in total, of which A has 25 and B has 25, all of which are distinct (ie. no overlap). How do I go about combining these 2 fields into one field. I'm using ArcMap 10.5.

Sample of What I Want

  • Have a look at gis.stackexchange.com/questions/252954/…
    – Midavalo
    Jun 17, 2019 at 16:23
  • @Midavalo I did see that but that's not what I'm looking for... I don't want to concatenate anything I simply want to populate the field with values from either A or B depending on which one even has a value. Please let me know if this is unclear and I'll edit the original question Jun 17, 2019 at 17:32
  • The link should work. Do you have None/Null values or empty strings?
    – BERA
    Jun 17, 2019 at 18:06
  • No I don't have any null values but that link does not describe what I'm looking for. Jun 17, 2019 at 18:10
  • I can't actually disclose that, but I will make a sample. Jun 17, 2019 at 18:13

2 Answers 2


If you don't want to use code you could use the field calculator with selections or definition query.

  1. Open the table
  2. Select by attribute/definition query where Field1 IS NOT NULL
  3. Field calculate field desiredresult = Field1
  4. Clear you selection query/definition query
  5. Add a new selection/definition query where Field2 IS NOT NULL
  6. Field calculate field desiredresult = Field2

Use Calculate Field / Field Calculator with python parser to calculate a third field: !fieldA! + !fieldB!

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