From 862753afbad4f27d4884ffde7dbc9d03ddf117f8 Mon Sep 17 00:00:00 2001
From: LiBinfeng <libinfeng@selectdb.com>
Date: Mon, 17 Mar 2025 19:35:57 +0800
Subject: [PATCH] [fix](Nereids) initcap constant folding should upper first
 character in all words (#49061)

---
 .../functions/executable/StringArithmetic.java        | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/executable/StringArithmetic.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/executable/StringArithmetic.java
index e54eb745e2b62d..87b817134e0922 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/executable/StringArithmetic.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/executable/StringArithmetic.java
@@ -420,12 +420,9 @@ public static Expression characterLength(StringLikeLiteral first) {
         return new IntegerLiteral(first.getValue().codePointCount(0, first.getValue().length()));
     }
 
-    private static boolean isSeparator(char c) {
-        if (".$|()[{^?*+\\".indexOf(c) == -1) {
-            return false;
-        } else {
-            return true;
-        }
+    private static boolean isAlphabetic(char c) {
+        Pattern pattern = Pattern.compile("\\p{Alnum}");
+        return pattern.matcher(String.valueOf(c)).find();
     }
 
     /**
@@ -437,7 +434,7 @@ public static Expression initCap(StringLikeLiteral first) {
         boolean capitalizeNext = true;
 
         for (char c : first.getValue().toCharArray()) {
-            if (Character.isWhitespace(c) || isSeparator(c)) {
+            if (Character.isWhitespace(c) || !isAlphabetic(c)) {
                 result.append(c);
                 capitalizeNext = true;  // Next character should be capitalized
             } else if (capitalizeNext) {