Christian Beikov ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *updated* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiNWQ2YjVmMzQ2... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-15531?atlOrigin=eyJpIjoiNWQ2Yj... ) HHH-15531 ( https://hibernate.atlassian.net/browse/HHH-15531?atlOrigin=eyJpIjoiNWQ2Yj... ) Use dense_rank instead of row_number when query uses dinstinct ( https://hibernate.atlassian.net/browse/HHH-15531?atlOrigin=eyJpIjoiNWQ2Yj... ) Change By: Christian Beikov ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) We have some code that adds {{row_number}} expressions like in the table based insert handler, which should rather use {{dense_rank}} or wrap a query in certain circumstances. See [https://hibernate.atlassian.net/browse/HHH-15517|https://hibernate.atlass...] for an example. Paraphrasing: If I rewrite the HQL to this (don’t select {{id}}, use {{distinct}} instead of {{group by}}): {code:sql}insert into TabData (col1, col2, col3) select distinct col1, col2, col3 from TabDataStaging{code} Hibernate 6 does the following: {code:sql}insert into HTE_tab_data(col1, col2, col3, rn_) (select distinct p2_0.col1, p2_0.col2, p2_0.col3, row_number() over () -- adding this column effectively disables the `distinct` from tab_data_staging p2_0);{code} Followed by the {{updates}} on the HTE table you were suspecting earlier: {code:sql}update HTE_tab_data set id=? where rn_=? update HTE_tab_data set id=? where rn_=? ...{code} Followed by {noformat}insert into tab_data(col1,col2,col3,id) select p1_0.col1,p1_0.col2,p1_0.col3,p1_0.id from HTE_tab_data p1_0{noformat} The final {{insert}} into {{tab_data}} can then fail due to unique constraint violation (I have a composite unique constraint on {{col1, col2, col3}}), because even though I’m using {{distinct}}, the {{row_number()}} clause added by Hibernate effectively disabled it… ( https://hibernate.atlassian.net/browse/HHH-15531#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-15531#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100207- sha1:866f7d8 )