Support distinct projection queries? #1202

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1. jgeewax

   added

   api: datastoreIssues related to the Datastore API.Issues related to the Datastore API.

   on Oct 22, 2015
2. jgeewax commented on Oct 22, 2015

   

   jgeewax

   on Oct 22, 2015

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   @pcostell : Can the API even allow this type of thing using a structured query object ? Or is this only supported via GQL ?
3. tseaver commented on Oct 22, 2015

   

   tseaver

   on Oct 22, 2015

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   Datastore queries take a projection parameter, which is a list of the fields to be returned. AFAICT, the API don't expose any way to do any "summary" operations (DISTINCT, COUNT, SUM, etc.) except to pull the values back and munge them client-side.
4. pcostell commented on Oct 22, 2015

   

   pcostell

   on Oct 22, 2015

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   Sorry OOO so short reply:
   Yes it can. In v1beta2 you can use group_by, in v1beta3 you can use distinct_on.

   SELECT DISTINCT p FROM Kind == SELECT p FROM KIND GROUP BY p.

   Aggregation ops aren't supported because they would require full scans of the data to answer. DISTINCT however can be implemented efficiently.
5. Fkawala commented on Oct 23, 2015

   

   Fkawala

   on Oct 23, 2015

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   @pcostell so the parameter group_by of object Query does what I expect, and there is not any interest (speed / efficiency ?) to use GQL SELECT DISTINCT ? Thanks.
6. pcostell commented on Oct 23, 2015

   

   pcostell

   on Oct 23, 2015

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   @Fkawala -- yes, using group_by on all your projection properties is the exact same as using SELECT DISTINCT IN GQL. (In fact that is how GQL DISTINCT is implemented.
7. dhermes commented on Dec 31, 2015

   

   dhermes

   on Dec 31, 2015

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   @pcostell I'm closing this out. It seems support already exists. LMK if I'm mistaken.
8. dhermes

   closed this as completedon Dec 31, 2015
9. JustinBeckwith

   assigned

   dhermes

   on Feb 1, 2021
10. parthea

    added a commit that references this issue on Jul 6, 2023

    Language v1 [(#1202)](GoogleCloudPlatform/python-docs-samples#1202)

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11. parthea

    added 2 commits that reference this issue on Nov 22, 2025

    feat: Add support for Proto and Enum types (#1202)

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    chore(main): release 0.63.3 (#1202)

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12. parthea

    added a commit that references this issue on Mar 2, 2026

    feat: Add support for Proto and Enum types (#1202)

    e9d8054