[jira] [Created] (SPARK-18578) Full outer join in correlated subquery returns incorrect results

["Nattavut Sutyanyong (JIRA)" <ji...@apache.org>]

Nattavut Sutyanyong created SPARK-18578:
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             Summary: Full outer join in correlated subquery returns incorrect results
                 Key: SPARK-18578
                 URL: https://issues.apache.org/jira/browse/SPARK-18578
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 2.0.0
            Reporter: Nattavut Sutyanyong


Full outer join with a correlated predicate in the left operand in a subquery may return incorrect results.

Example:
{code}
Seq(1).toDF("c1").createOrReplaceTempView("t1")
Seq(2).toDF("c1").createOrReplaceTempView("t2")
Seq(1).toDF("c1").createOrReplaceTempView("t3")

// Test case: 01 EXISTS subquery context
// Expected result: 1 row
// Actual result:   0 row
sql("select * from t1 where exists (select 1 from (select c1 from t2 where t1.c1 = 2) t2 full join t3 on t2.c1=t3.c1)").show

// Test case: 02 Scalar subquery context
// Expected result: 1 row of value 1
// Actual result:   1 row of NULL
// Note adding the meaningless equi-join T1.c1=T2.c1 to get through the CROSS JOIN restriction
sql("select (select max(1) from (select c1 from t2 where t1.c1 = 2 and t1.c1=t2.c1) t2 full join t3 on t2.c1=t3.c1) from t1").show
{code}



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