Fix array_join adding extra delimeter if last element is null

prestodb · May 2, 2024 · ed10b16 · ed10b16
1 parent 902c426
commit ed10b16
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Showing 2 changed files with 12 additions and 9 deletions.
diff --git a/presto-main/src/main/java/com/facebook/presto/operator/scalar/ArrayJoin.java b/presto-main/src/main/java/com/facebook/presto/operator/scalar/ArrayJoin.java
@@ -315,15 +315,19 @@ public static void arrayJoinProvidedBlock(
             Slice nullReplacement)
     {
         int numElements = arrayBlock.getPositionCount();
+        boolean hasOutput = false;
 
         for (int i = 0; i < numElements; i++) {
+            if (arrayBlock.isNull(i) && nullReplacement == null) {
+                continue;
+            }
+
+            if (hasOutput) {
+                blockBuilder.writeBytes(delimiter, 0, delimiter.length());
+            }
+
             if (arrayBlock.isNull(i)) {
-                if (nullReplacement != null) {
-                    blockBuilder.writeBytes(nullReplacement, 0, nullReplacement.length());
-                }
-                else {
-                    continue;
-                }
+                blockBuilder.writeBytes(nullReplacement, 0, nullReplacement.length());
             }
             else {
                 try {
@@ -337,9 +341,7 @@ public static void arrayJoinProvidedBlock(
                 }
             }
 
-            if (i != numElements - 1) {
-                blockBuilder.writeBytes(delimiter, 0, delimiter.length());
-            }
+            hasOutput = true;
         }
 
         blockBuilder.closeEntry();

diff --git a/presto-main/src/test/java/com/facebook/presto/type/TestArrayOperators.java b/presto-main/src/test/java/com/facebook/presto/type/TestArrayOperators.java
@@ -617,6 +617,7 @@ public void testArrayJoin()
         assertFunction("array_join(ARRAY[1, NULL, 2], ',')", VARCHAR, "1,2");
         assertFunction("ARRAY_JOIN(ARRAY [1, 2, 3], ';', 'N/A')", VARCHAR, "1;2;3");
         assertFunction("ARRAY_JOIN(ARRAY [1, 2, null], ';', 'N/A')", VARCHAR, "1;2;N/A");
+        assertFunction("ARRAY_JOIN(ARRAY [1, 2, null], ';')", VARCHAR, "1;2");
         assertFunction("ARRAY_JOIN(ARRAY [1, 2, 3], 'x')", VARCHAR, "1x2x3");
         assertFunction("ARRAY_JOIN(ARRAY [BIGINT '1', 2, 3], 'x')", VARCHAR, "1x2x3");
         assertFunction("ARRAY_JOIN(ARRAY [null], '=')", VARCHAR, "");