I'm trying to de-duplicate records by a particular field. I'm getting an error when I try a GROUP BY in my query.

An error occurred while checking the query syntax. Errors: Column 'C7226490.MyDataExt.FieldOne' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

This is the query I used:

SELECT FieldOne, FieldTwo, COUNT(FieldThree)
FROM MyDataExt

Does anyone know why I can't use this GROUP BY query? The error does go away if and only if I put every single field that I used in my SELECT into the GROUP BY. That, however, is not what I want. And I'm not certain why my COUNT() isn't being recognized as an aggregate.

  • 1
    In this query you need to add FieldTwo to the GROUP BY clause, if you are not aggregating it Commented Nov 13, 2017 at 17:33

1 Answer 1


What do you expect to be queried for fieldTwo? The values might be different for one result row, that's why it won't let you. Imagine the following data example :

f1| f2
a | b
a | b
a | c

If you now goup by f1 only (a), f2 will be invalid cause it is b and c at the same time. Therefore you either need to group by both or get rid of f2.

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