diff --git a/velox/functions/sparksql/ConcatWs.cpp b/velox/functions/sparksql/ConcatWs.cpp
index b477086165d2c..f51c5a7932cdd 100644
--- a/velox/functions/sparksql/ConcatWs.cpp
+++ b/velox/functions/sparksql/ConcatWs.cpp
@@ -59,10 +59,9 @@ class ConcatWs : public exec::VectorFunction {
         if (decodedArrays[i]->isNullAt(row)) {
           continue;
         }
-        auto arrayVector = arrayVectors[i];
         auto indices = decodedArrays[i].get()->indices();
-        auto size = arrayVector->sizeAt(indices[row]);
-        auto offset = arrayVector->offsetAt(indices[row]);
+        auto size = arrayVectors[i]->sizeAt(indices[row]);
+        auto offset = arrayVectors[i]->offsetAt(indices[row]);
 
         for (int j = 0; j < size; ++j) {
           if (!elementsDecodedVectors[i].isNullAt(offset + j)) {
@@ -97,7 +96,7 @@ class ConcatWs : public exec::VectorFunction {
         totalResultBytes += value.size();
       }
 
-      int32_t separatorSize = isConstantSeparator()
+      auto separatorSize = isConstantSeparator()
           ? separator_.value().size()
           : decodedSeparator->valueAt<StringView>(row).size();
 
@@ -235,15 +234,11 @@ class ConcatWs : public exec::VectorFunction {
           isFirst = false;
         } else {
           // Add separator before the current value.
-          if (!separator.empty()) {
-            memcpy(rawBuffer, separator.data(), separator.size());
-            rawBuffer += separator.size();
-          }
-        }
-        if (!value.empty()) {
-          memcpy(rawBuffer, value.data(), value.size());
-          rawBuffer += value.size();
+          memcpy(rawBuffer, separator.data(), separator.size());
+          rawBuffer += separator.size();
         }
+        memcpy(rawBuffer, value.data(), value.size());
+        rawBuffer += value.size();
       };
 
       for (auto itArgs = args.begin() + 1; itArgs != args.end(); ++itArgs) {
@@ -252,10 +247,9 @@ class ConcatWs : public exec::VectorFunction {
             ++i;
             continue;
           }
-          auto arrayVector = arrayVectors[i];
           auto indices = decodedArrays[i].get()->indices();
-          auto size = arrayVector->sizeAt(indices[row]);
-          auto offset = arrayVector->offsetAt(indices[row]);
+          auto size = arrayVectors[i]->sizeAt(indices[row]);
+          auto offset = arrayVectors[i]->offsetAt(indices[row]);
 
           for (int k = 0; k < size; ++k) {
             if (!elementsDecodedVectors[i].isNullAt(offset + k)) {