Github user amansinha100 commented on a diff in the pull request:
https://github.com/apache/drill/pull/1071#discussion_r158322278
--- Diff:
exec/java-exec/src/test/java/org/apache/drill/TestUnionDistinct.java ---
@@ -754,4 +756,37 @@ public void testDrill4147_1() throws Exception {
}
}
+ @Test
+ public void testUnionWithManyColumns() throws Exception {
--- End diff --
Perhaps the confusion is with union-all vs. union-distinct. UNION (without
the following ALL or DISTINCT keyword) is interpreted as DISTINCT and as
@arina-ielchiieva 's example shows, it currently is processed in 2 steps:
union-all followed by a distinct (group-by).
As a separate enhancement, unless a JIRA already exists, we should file one
to natively support union-distinct within the same operator.
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