[SPARK-19017][SQL] NOT IN subquery with more than one column may return incorrect results

## What changes were proposed in this pull request?

This PR fixes the code in Optimizer phase where the NULL-aware expression of a NOT IN query is expanded in Rule `RewritePredicateSubquery`.

Example:
The query

 select a1,b1
 from   t1
 where  (a1,b1) not in (select a2,b2
                        from   t2);

has the (a1, b1) = (a2, b2) rewritten from (before this fix):

Join LeftAnti, ((isnull((_1#2 = a2#16)) || isnull((_2#3 = b2#17))) || ((_1#2 = a2#16) && (_2#3 = b2#17)))

to (after this fix):

Join LeftAnti, (((_1#2 = a2#16) || isnull((_1#2 = a2#16))) && ((_2#3 = b2#17) || isnull((_2#3 = b2#17))))

## How was this patch tested?

sql/test, catalyst/test and new test cases in SQLQueryTestSuite.

Author: Nattavut Sutyanyong <[email protected]>

Closes apache#16467 from nsyca/19017.

Author: nsyca

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/subquery.scala

@@ -68,8 +68,14 @@ object RewritePredicateSubquery extends Rule[LogicalPlan] with PredicateHelper {
           // Note that will almost certainly be planned as a Broadcast Nested Loop join.
           // Use EXISTS if performance matters to you.
           val (joinCond, outerPlan) = rewriteExistentialExpr(conditions, p)
-          val anyNull = splitConjunctivePredicates(joinCond.get).map(IsNull).reduceLeft(Or)
-          Join(outerPlan, sub, LeftAnti, Option(Or(anyNull, joinCond.get)))
+          // Expand the NOT IN expression with the NULL-aware semantic
+          // to its full form. That is from:
+          //   (a1,b1,...) = (a2,b2,...)
+          // to
+          //   (a1=a2 OR isnull(a1=a2)) AND (b1=b2 OR isnull(b1=b2)) AND ...
+          val joinConds = splitConjunctivePredicates(joinCond.get)
+          val pairs = joinConds.map(c => Or(c, IsNull(c))).reduceLeft(And)
+          Join(outerPlan, sub, LeftAnti, Option(pairs))
         case (p, predicate) =>
           val (newCond, inputPlan) = rewriteExistentialExpr(Seq(predicate), p)
           Project(p.output, Filter(newCond.get, inputPlan))

sql/core/src/test/resources/sql-tests/inputs/subquery/in-subquery/not-in-multiple-columns.sql

@@ -0,0 +1,55 @@
+-- This file contains test cases for NOT IN subquery with multiple columns.
+
+-- The data sets are populated as follows:
+-- 1) When T1.A1 = T2.A2
+--    1.1) T1.B1 = T2.B2
+--    1.2) T1.B1 = T2.B2 returns false
+--    1.3) T1.B1 is null
+--    1.4) T2.B2 is null
+-- 2) When T1.A1 = T2.A2 returns false
+-- 3) When T1.A1 is null
+-- 4) When T1.A2 is null
+
+-- T1.A1  T1.B1     T2.A2  T2.B2
+-- -----  -----     -----  -----
+--     1      1         1      1    (1.1)
+--     1      3                     (1.2)
+--     1   null         1   null    (1.3 & 1.4)
+--
+--     2      1         1      1    (2)
+--  null      1                     (3)
+--                   null      3    (4)
+
+create temporary view t1 as select * from values
+  (1, 1), (2, 1), (null, 1),
+  (1, 3), (null, 3),
+  (1, null), (null, 2)
+as t1(a1, b1);
+
+create temporary view t2 as select * from values
+  (1, 1),
+  (null, 3),
+  (1, null)
+as t2(a2, b2);
+
+-- multiple columns in NOT IN
+-- TC 01.01
+select a1,b1
+from   t1
+where  (a1,b1) not in (select a2,b2
+                       from   t2);
+
+-- multiple columns with expressions in NOT IN
+-- TC 01.02
+select a1,b1
+from   t1
+where  (a1-1,b1) not in (select a2,b2
+                         from   t2);
+
+-- multiple columns with expressions in NOT IN
+-- TC 01.02
+select a1,b1
+from   t1
+where  (a1,b1) not in (select a2+1,b2
+                       from   t2);
+

sql/core/src/test/resources/sql-tests/results/subquery/in-subquery/not-in-multiple-columns.sql.out

@@ -0,0 +1,59 @@
+-- Automatically generated by SQLQueryTestSuite
+-- Number of queries: 5
+
+
+-- !query 0
+create temporary view t1 as select * from values
+  (1, 1), (2, 1), (null, 1),
+  (1, 3), (null, 3),
+  (1, null), (null, 2)
+as t1(a1, b1)
+-- !query 0 schema
+struct<>
+-- !query 0 output
+
+
+
+-- !query 1
+create temporary view t2 as select * from values
+  (1, 1),
+  (null, 3),
+  (1, null)
+as t2(a2, b2)
+-- !query 1 schema
+struct<>
+-- !query 1 output
+
+
+
+-- !query 2
+select a1,b1
+from   t1
+where  (a1,b1) not in (select a2,b2
+                       from   t2)
+-- !query 2 schema
+struct<a1:int,b1:int>
+-- !query 2 output
+2	1
+
+
+-- !query 3
+select a1,b1
+from   t1
+where  (a1-1,b1) not in (select a2,b2
+                         from   t2)
+-- !query 3 schema
+struct<a1:int,b1:int>
+-- !query 3 output
+1	1
+
+
+-- !query 4
+select a1,b1
+from   t1
+where  (a1,b1) not in (select a2+1,b2
+                       from   t2)
+-- !query 4 schema
+struct<a1:int,b1:int>
+-- !query 4 output
+1	1

sql/core/src/test/scala/org/apache/spark/sql/SQLQueryTestSuite.scala

@@ -163,7 +163,12 @@ class SQLQueryTestSuite extends QueryTest with SharedSQLContext {
         s"-- Number of queries: ${outputs.size}\n\n\n" +
         outputs.zipWithIndex.map{case (qr, i) => qr.toString(i)}.mkString("\n\n\n") + "\n"
       }
-      stringToFile(new File(testCase.resultFile), goldenOutput)
+      val resultFile = new File(testCase.resultFile);
+      val parent = resultFile.getParentFile();
+      if (!parent.exists()) {
+        assert(parent.mkdirs(), "Could not create directory: " + parent)
+      }
+      stringToFile(resultFile, goldenOutput)
     }
 
     // Read back the golden file.

sql/core/src/test/scala/org/apache/spark/sql/SubquerySuite.scala

@@ -263,12 +263,12 @@ class SubquerySuite extends QueryTest with SharedSQLContext {
       Row(1, 2.0) :: Row(1, 2.0) :: Nil)
 
     checkAnswer(
-      sql("select * from l where a not in (select c from t where b < d)"),
-      Row(1, 2.0) :: Row(1, 2.0) :: Row(3, 3.0) :: Nil)
+      sql("select * from l where (a, b) not in (select c, d from t) and a < 4"),
+      Row(1, 2.0) :: Row(1, 2.0) :: Row(2, 1.0) :: Row(2, 1.0) :: Row(3, 3.0) :: Nil)
 
     // Empty sub-query
     checkAnswer(
-      sql("select * from l where a not in (select c from r where c > 10 and b < d)"),
+      sql("select * from l where (a, b) not in (select c, d from r where c > 10)"),
       Row(1, 2.0) :: Row(1, 2.0) :: Row(2, 1.0) :: Row(2, 1.0) ::
       Row(3, 3.0) :: Row(null, null) :: Row(null, 5.0) :: Row(6, null) :: Nil)