Fix null separator provided only

PHILO-HE · Mar 26, 2024 · c58f5cf · c58f5cf
1 parent fe68088
commit c58f5cf
Showing 1 changed file with 6 additions and 5 deletions.
diff --git a/velox/functions/sparksql/String.cpp b/velox/functions/sparksql/String.cpp
@@ -303,17 +303,18 @@ class ConcatWs : public exec::VectorFunction {
     context.ensureWritable(selected, VARCHAR(), result);
     auto flatResult = result->asFlatVector<StringView>();
     auto numArgs = args.size();
+    // If separator is NULL, result is NULL.
+    if (args[0]->isNullAt(0)) {
+      selected.applyToSelected([&](int row) { result->setNull(row, true); });
+      return;
+    }
+    // If only separator (not a NULL) is provided, result is an empty array.
     if (numArgs == 1) {
       selected.applyToSelected(
           [&](int row) { flatResult->setNoCopy(row, StringView("")); });
       return;
     }
 
-    if (args[0]->isNullAt(0)) {
-      selected.applyToSelected([&](int row) { result->setNull(row, true); });
-      return;
-    }
-
     auto arrayArgs = args[1]->typeKind() == TypeKind::ARRAY;
     if (arrayArgs) {
       concatWsArray(selected, args, context, connector_, *flatResult);