diff --git a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/metadata/view/ViewExpressionToStringTest.java b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/metadata/view/ViewExpressionToStringTest.java
index 3f90b8bf410e..1b7b346769aa 100644
--- a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/metadata/view/ViewExpressionToStringTest.java
+++ b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/metadata/view/ViewExpressionToStringTest.java
@@ -41,7 +41,7 @@ public class ViewExpressionToStringTest {
 
   @Test
   public void testTimseriesOperand() {
-    String fullPath = new String("root.db.device.s01");
+    String fullPath = "root.db.device.s01";
     TimeSeriesViewOperand timeSeriesViewOperand = new TimeSeriesViewOperand(fullPath);
     Assert.assertEquals(fullPath, timeSeriesViewOperand.toString());
     Assert.assertEquals(fullPath, timeSeriesViewOperand.toString(true));
@@ -55,8 +55,8 @@ public void testAdditionViewExpression() {
     AdditionViewExpression add =
         new AdditionViewExpression(timeSeriesViewOperand, constantViewOperand);
 
-    String expectedRoot = new String("root.db.device.s01 + 2");
-    String expectedNotRoot = new String("(root.db.device.s01 + 2)");
+    String expectedRoot = "root.db.device.s01 + 2";
+    String expectedNotRoot = "(root.db.device.s01 + 2)";
     Assert.assertEquals(expectedRoot, add.toString());
     Assert.assertEquals(expectedRoot, add.toString(true));
     Assert.assertEquals(expectedNotRoot, add.toString(false));
@@ -70,8 +70,8 @@ public void testTwoBinaryExpression() {
     TimeSeriesViewOperand ts2 = new TimeSeriesViewOperand("root.ln.d.s01");
     MultiplicationViewExpression multiplication = new MultiplicationViewExpression(add, ts2);
 
-    String expectedRoot = new String("(root.db.device.s01 + 2) * root.ln.d.s01");
-    String expectedNotRoot = new String("((root.db.device.s01 + 2) * root.ln.d.s01)");
+    String expectedRoot = "(root.db.device.s01 + 2) * root.ln.d.s01";
+    String expectedNotRoot = "((root.db.device.s01 + 2) * root.ln.d.s01)";
     Assert.assertEquals(expectedRoot, multiplication.toString());
     Assert.assertEquals(expectedRoot, multiplication.toString(true));
     Assert.assertEquals(expectedNotRoot, multiplication.toString(false));
@@ -82,8 +82,8 @@ public void testFunctionViewExpression01() {
     String functionName = "func";
     FunctionViewExpression func = new FunctionViewExpression(functionName);
 
-    String expectedRoot = new String("func()");
-    String expectedNotRoot = new String("func()");
+    String expectedRoot = "func()";
+    String expectedNotRoot = "func()";
     Assert.assertEquals(expectedRoot, func.toString());
     Assert.assertEquals(expectedRoot, func.toString(true));
     Assert.assertEquals(expectedNotRoot, func.toString(false));
@@ -103,8 +103,8 @@ public void testFunctionViewExpression02() {
 
     FunctionViewExpression func = new FunctionViewExpression(functionName, keys, values, exps);
 
-    String expectedRoot = new String("MAX(root.db.device.s01 + 2, root.ln.d.s01)");
-    String expectedNotRoot = new String("MAX(root.db.device.s01 + 2, root.ln.d.s01)");
+    String expectedRoot = "MAX(root.db.device.s01 + 2, root.ln.d.s01)";
+    String expectedNotRoot = "MAX(root.db.device.s01 + 2, root.ln.d.s01)";
     Assert.assertEquals(expectedRoot, func.toString());
     Assert.assertEquals(expectedRoot, func.toString(true));
     Assert.assertEquals(expectedNotRoot, func.toString(false));
@@ -121,8 +121,8 @@ public void testFunctionViewExpression03() {
 
     FunctionViewExpression func = new FunctionViewExpression(functionName, keys, values, exps);
 
-    String expectedRoot = new String("CAST(type=INT32)(root.ln.d.s01)");
-    String expectedNotRoot = new String("CAST(type=INT32)(root.ln.d.s01)");
+    String expectedRoot = "CAST(root.ln.d.s01, type=INT32)";
+    String expectedNotRoot = "CAST(root.ln.d.s01, type=INT32)";
     Assert.assertEquals(expectedRoot, func.toString());
     Assert.assertEquals(expectedRoot, func.toString(true));
     Assert.assertEquals(expectedNotRoot, func.toString(false));
@@ -139,8 +139,8 @@ public void testFunctionViewExpression04() {
 
     FunctionViewExpression func = new FunctionViewExpression(functionName, keys, values, exps);
 
-    String expectedRoot = new String("CAST(type=INT32)(root.ln.d.s01)");
-    String expectedNotRoot = new String("CAST(type=INT32)(root.ln.d.s01)");
+    String expectedRoot = "CAST(root.ln.d.s01, type=INT32)";
+    String expectedNotRoot = "CAST(root.ln.d.s01, type=INT32)";
     Assert.assertEquals(expectedRoot, func.toString());
     Assert.assertEquals(expectedRoot, func.toString(true));
     Assert.assertEquals(expectedNotRoot, func.toString(false));
@@ -158,10 +158,8 @@ public void testFunctionViewExpression05() {
 
     FunctionViewExpression func = new FunctionViewExpression(functionName, keys, values, exps);
 
-    String expectedRoot =
-        new String("FUNC(type=INT32, key=value)(root.db.device.s01, root.ln.d.s01)");
-    String expectedNotRoot =
-        new String("FUNC(type=INT32, key=value)(root.db.device.s01, root.ln.d.s01)");
+    String expectedRoot = "FUNC(root.db.device.s01, root.ln.d.s01, type=INT32, key=value)";
+    String expectedNotRoot = "FUNC(root.db.device.s01, root.ln.d.s01, type=INT32, key=value)";
     Assert.assertEquals(expectedRoot, func.toString());
     Assert.assertEquals(expectedRoot, func.toString(true));
     Assert.assertEquals(expectedNotRoot, func.toString(false));
@@ -174,8 +172,8 @@ public void testBetweenViewExpression() {
     TimeSeriesViewOperand ts1 = new TimeSeriesViewOperand("root.db.device.s01");
     BetweenViewExpression exp = new BetweenViewExpression(ts1, timestamp01, timestamp02);
 
-    String expectedRoot = new String("root.db.device.s01 BETWEEN TIMESTAMP AND TIMESTAMP");
-    String expectedNotRoot = new String("(root.db.device.s01 BETWEEN TIMESTAMP AND TIMESTAMP)");
+    String expectedRoot = "root.db.device.s01 BETWEEN TIMESTAMP AND TIMESTAMP";
+    String expectedNotRoot = "(root.db.device.s01 BETWEEN TIMESTAMP AND TIMESTAMP)";
     Assert.assertEquals(expectedRoot, exp.toString());
     Assert.assertEquals(expectedRoot, exp.toString(true));
     Assert.assertEquals(expectedNotRoot, exp.toString(false));
diff --git a/iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/schema/view/viewExpression/multi/FunctionViewExpression.java b/iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/schema/view/viewExpression/multi/FunctionViewExpression.java
index 58bc00286fd8..0d1c700387af 100644
--- a/iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/schema/view/viewExpression/multi/FunctionViewExpression.java
+++ b/iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/schema/view/viewExpression/multi/FunctionViewExpression.java
@@ -34,7 +34,7 @@
 
 public class FunctionViewExpression extends ViewExpression {
 
-  // region member variables and init functions
+  /** region member variables and init functions */
   private final String functionName;
 
   /**
@@ -70,8 +70,7 @@ public FunctionViewExpression(
       }
     } else {
       String errorMsg =
-          String.format(
-              "Illegal parameters during FunctionExpression construction. Array length mismatch.");
+          "Illegal parameters during FunctionExpression construction. Array length mismatch.";
       throw new RuntimeException(errorMsg);
     }
     this.expressions = expressions;
@@ -116,10 +115,7 @@ public ViewExpressionType getExpressionType() {
   @Override
   protected boolean isLeafOperandInternal() {
     // if this expression has no children, return true; else return false.
-    if (this.expressions.size() == 0) {
-      return true;
-    }
-    return false;
+    return this.expressions.isEmpty();
   }
 
   @Override
@@ -131,8 +127,21 @@ public List<ViewExpression> getChildViewExpressions() {
   public String toString(boolean isRoot) {
     StringBuilder result = new StringBuilder(this.functionName);
     int keyValueSize = this.functionAttributesKeyValueList.size();
+
+    result.append("(");
+    for (int i = 0; i < this.expressions.size(); i++) {
+      result.append(this.expressions.get(i).toString());
+      if (i + 1 >= this.expressions.size()) {
+        break;
+      }
+      result.append(", ");
+    }
+
     if (this.functionAttributesKeyValueList.size() > 1) {
-      result.append("(");
+      if (!this.expressions.isEmpty()) {
+        result.append(", ");
+      }
+
       for (int i = 0; i + 1 < keyValueSize; i += 2) {
         result
             .append(this.functionAttributesKeyValueList.get(i))
@@ -143,16 +152,8 @@ public String toString(boolean isRoot) {
         }
         result.append(", ");
       }
-      result.append(")");
-    }
-    result.append("(");
-    for (int i = 0; i < this.expressions.size(); i++) {
-      result.append(this.expressions.get(i).toString());
-      if (i + 1 >= this.expressions.size()) {
-        break;
-      }
-      result.append(", ");
     }
+
     result.append(")");
     return result.toString();
   }