Different results for a query with GROUP BY and SUM(1) (summation of the number 1) when there is a LEFT or INNER JOIN involved ------------------------------------------------------------------------------------------------------------------------------ Key: TEIID-5354 URL: https://issues.jboss.org/browse/TEIID-5354 Project: Teiid Issue Type: Bug Components: Query Engine Affects Versions: 10.2 Environment: teiid-10.2.0 on WildFly Full 11.0.0.Final (WildFly Core 3.0.8.Final) Reporter: dalex dalex Assignee: Steven Hawkins Priority: Blocker Fix For: 11.0, 10.3.2, 10.2.3 Attachments: address_pg.sql, stateprovince_mysql.sql Teiid returns different results for a query with GROUP BY and SUM(1) (summation of the number 1) when there is a LEFT or INNER JOIN involved. There are two problems: a) incorrect check in MergeJoinStrategy.compareToPrevious method which generates TEIID31202 exception and b) a bug in algorithm of join itself which leads to incorrect results. To reproduce the bug, please, run the following queries and compare theSum and theCount column values: {code:sql} select r.city, sum(1) as theSum ,count(*) as theCount from "dsp.address_pg" r left join "adventureworks.stateprovince" c on "r.stateprovinceid" = "c.stateprovinceid" group by r.city order by r.city ;; {code} {code:sql} select r.city, sum(1) as theSum ,count(*) as theCount from "dsp.address_pg" r inner join "adventureworks.stateprovince" c on "r.stateprovinceid" = "c.stateprovinceid" group by r.city order by r.city ;; {code} but the following queries return correct results: {code:sql} select r.city, sum(1) as theSum ,count(*) as theCount from "dsp.address_pg" r right join "adventureworks.stateprovince" c on "r.stateprovinceid" = "c.stateprovinceid" group by r.city order by r.city ;; {code} the second one is also correct (LEFT JOIN) but uses window function: {code:sql} select distinct city, sum(1) OVER (PARTITION BY city) as theSum ,count(*) OVER (PARTITION BY city) as theCount from "dsp.address_pg" r left join "adventureworks.stateprovince" c on "r.stateprovinceid" = "c.stateprovinceid" order by r.city ;; {code}