[fix](nereids) convert stringLikeLiteral to double should use byte le…

…ngth (apache#43776)

The optimizer maps different data types to Double, allowing for a
unified comparison of literals.
StringLikeLiteral is regarded as a long int, and map the long int to
double.
To extract the first N bytes from a string, you should use
String.getBytes().length instead of String.length().

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/literal/StringLikeLiteral.java

@@ -46,11 +46,12 @@ public double getDouble() {
      * get double value
      */
     public static double getDouble(String str) {
+        byte[] bytes = str.getBytes();
         long v = 0;
         int pos = 0;
-        int len = Math.min(str.length(), 7);
+        int len = Math.min(bytes.length, 7);
         while (pos < len) {
-            v += Byte.toUnsignedLong(str.getBytes()[pos]) << ((6 - pos) * 8);
+            v += Byte.toUnsignedLong(bytes[pos]) << ((6 - pos) * 8);
             pos++;
         }
         return (double) v;

fe/fe-core/src/test/java/org/apache/doris/nereids/trees/expressions/literal/StringLikeLiteralTest.java

@@ -0,0 +1,34 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.nereids.trees.expressions.literal;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class StringLikeLiteralTest {
+    @Test
+    public void testStrToDouble() {
+        // fix bug: maxStr.length = 4, maxStr.getBytes().length=12
+        // when converting str to double, bytes length is used instead of string length
+        String minStr = "商家+店长+场地+设备类型维度";
+        String maxStr = "商家维度";
+        double d1 = StringLikeLiteral.getDouble(minStr);
+        double d2 = StringLikeLiteral.getDouble(maxStr);
+        Assertions.assertTrue(d1 < d2);
+    }
+}