Fixing bug: IS DISTINCT FROM NULL should work for NULL column values

prestodb · Sep 17, 2020 · d79804d · d79804d
1 parent ee1627e
commit d79804d
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Showing 2 changed files with 46 additions and 2 deletions.
diff --git a/presto-main/src/main/java/com/facebook/presto/sql/planner/ExpressionInterpreter.java b/presto-main/src/main/java/com/facebook/presto/sql/planner/ExpressionInterpreter.java
@@ -743,7 +743,10 @@ protected Object visitComparisonExpression(ComparisonExpression node, Object con
                 if (left == null && right == null) {
                     return false;
                 }
-                else if (left == null || right == null) {
+                else if (left == null && !hasUnresolvedValue(right)) {
+                    return true;
+                }
+                else if (right == null && !hasUnresolvedValue(left)) {
                     return true;
                 }
             }
@@ -1272,7 +1275,13 @@ private List<Type> types(Expression... types)
 
         private boolean hasUnresolvedValue(Object... values)
         {
-            return hasUnresolvedValue(ImmutableList.copyOf(values));
+            ArrayList<Object> valuesList = new ArrayList<>(values.length);
+            for (Object value : values) {
+                if (value != null) {
+                    valuesList.add(value);
+                }
+            }
+            return !valuesList.isEmpty() && hasUnresolvedValue(valuesList);
         }
 
         private boolean hasUnresolvedValue(List<Object> values)

diff --git a/presto-tests/src/main/java/com/facebook/presto/tests/AbstractTestQueries.java b/presto-tests/src/main/java/com/facebook/presto/tests/AbstractTestQueries.java
@@ -5344,4 +5344,39 @@ public void testMultipleSqlFunctionsWithLambda()
                 "SELECT array_sum(zip_with(a, b, (x, y) -> x * y)), array_sum(zip_with(a, b, (x, y) -> x * y)) + array_sum(zip_with(a, a, (x, y) -> x * y)) FROM (VALUES (ARRAY[1, 2, 3], ARRAY[1, 0, 0])) t(a, b)",
                 "SELECT 1, 15");
     }
+
+    @Test
+    public void testDistinctFrom()
+    {
+        assertQuery(
+                "SELECT x IS DISTINCT FROM NULL FROM (SELECT CAST(NULL AS VARCHAR)) T(x)",
+                "SELECT FALSE");
+        assertQuery(
+                "SELECT NULL IS DISTINCT FROM x FROM (SELECT CAST(NULL AS VARCHAR)) T(x)",
+                "SELECT FALSE");
+        assertQuery(
+                "SELECT x IS DISTINCT FROM NULL FROM (SELECT CAST('something' AS VARCHAR)) T(x)",
+                "SELECT TRUE");
+        assertQuery(
+                "SELECT NULL IS DISTINCT FROM x FROM (SELECT CAST('something' AS VARCHAR)) T(x)",
+                "SELECT TRUE");
+        assertQuery(
+                "SELECT R.name IS DISTINCT FROM NULL FROM nation N LEFT OUTER JOIN region R ON N.regionkey = R.regionkey AND R.regionkey = 2 WHERE N.name='GERMANY'",
+                "SELECT FALSE");
+        assertQuery(
+                "SELECT NULL IS DISTINCT FROM R.name FROM nation N LEFT OUTER JOIN region R ON N.regionkey = R.regionkey AND R.regionkey = 2 WHERE N.name='KENYA'",
+                "SELECT FALSE");
+        assertQuery(
+                "SELECT NULL IS DISTINCT FROM R.name FROM nation N LEFT OUTER JOIN region R ON N.regionkey = R.regionkey AND R.regionkey = 2 WHERE N.name='KENYA'",
+                "SELECT FALSE");
+        assertQuery(
+                "SELECT NULL IS DISTINCT FROM R.name FROM nation N LEFT OUTER JOIN region R ON N.regionkey = R.regionkey AND R.regionkey = 2 WHERE N.name='KENYA'",
+                "SELECT FALSE");
+        assertQuery(
+                "SELECT NULL IS DISTINCT FROM R.name FROM nation N LEFT OUTER JOIN region R ON N.regionkey = R.regionkey AND R.regionkey = 2 WHERE N.name='INDIA'",
+                "SELECT TRUE");
+        assertQuery(
+                "SELECT NULL IS DISTINCT FROM R.name FROM nation N LEFT OUTER JOIN region R ON N.regionkey = R.regionkey AND R.regionkey = 2 WHERE N.name='JAPAN'",
+                "SELECT TRUE");
+    }
 }