Details
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Bug
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Status: Closed
-
Major
-
Resolution: Fixed
-
None
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None
Description
Druid queries that have joins against self table gives wrong results.
e.g.
SELECT
username AS `username`,
SUM(double1) AS `sum_double1`
FROM
druid_table_with_nulls `tbl1`
JOIN (
SELECT
username AS `username`,
SUM(double1) AS `sum_double2`
FROM druid_table_with_nulls
GROUP BY `username`
ORDER BY `sum_double2`
DESC LIMIT 10
)
`tbl2`
ON (`tbl1`.`username` = `tbl2`.`username`)
GROUP BY `tbl1`.`username`;
In this case one of the queries is a druid scan query and other is groupBy query.
During planning, the properties of these queries are set to the tableDesc and serdeInfo, while setting the map work, we overwrite the properties from the properties present in serdeInfo, this causes the scan query results to be deserialized using wrong column names and results in Null values.