OpenJPA: how to construct a GROUP BY query with a group count
In JPQL I want to construct the equivalent query to this:
select *, count(*) as finger_count from page_delta_summary
where delta_history_id = ? and change_type = ? group by fingerprint;
where fingerprint
is a varchar field in table page_delta_summary
. What I have is this:
select d, count(d) as finger_count from PageDeltaSummary d
where d.deltaHistoryId = :deltaHistoryId and d.type = :pageDeltaType
GROUP BY d.fingerprint"
where PageDeltaSummary
is my entity. But I'm getting the following exception:
org.apache.openjpa.persistence.ArgumentExcepti开发者_运维技巧on: Your query on type "class com.su3analytics.sitedelta.model.PageDeltaSummary" with filter "select d, count(d) from PageDeltaSummary d where d.deltaHistoryId = :deltaHistoryId and d.type = :pageDeltaType GROUP BY d.fingerprint" is invalid. Your select and having clauses must only include aggregates or values that also appear in your grouping clause.
The query works fine if I remove either count(d) as finger_count or the GROUP BY.
Any suggestions?
Thanks
Your original SQL query doesn't make sense, therefore you can't convert in into JPQL.
I guess you want to get count of page_delta_summary
rows satisfying where
conditions for each fingerprint
. If so, the SQL query looks like this:
select fingerprint, count(*) as finger_count from page_delta_summary
where delta_history_id = ? and change_type = ? group by fingerprint;
and JPQL - like this:
select d.fingerprint, count(d) from PageDeltaSummary d
where d.deltaHistoryId = :deltaHistoryId and d.type = :pageDeltaType
GROUP BY d.fingerprint
These queries return pairs <fingerprint
, finger_count
> instead of full page_delta_summary
rows (or entities).
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