diff --git a/docs/.vuepress/sidebar/en.js b/docs/.vuepress/sidebar/en.js
index c09cc54fb1..eb85411c9b 100644
--- a/docs/.vuepress/sidebar/en.js
+++ b/docs/.vuepress/sidebar/en.js
@@ -197,6 +197,7 @@ module.exports = [
             children: [
               "append_trailing_char_if_absent",
               "ascii",
+              "char_length",
               "concat",
               "concat_ws",
               "ends_with",
diff --git a/docs/.vuepress/sidebar/zh-CN.js b/docs/.vuepress/sidebar/zh-CN.js
index e58c3709bd..bb4cc67a4c 100644
--- a/docs/.vuepress/sidebar/zh-CN.js
+++ b/docs/.vuepress/sidebar/zh-CN.js
@@ -209,6 +209,7 @@ module.exports = [
             children: [
               "append_trailing_char_if_absent",
               "ascii",
+              "char_length",
               "concat",
               "concat_ws",
               "ends_with",
diff --git a/docs/en/sql-reference/sql-functions/string-functions/char_length.md b/docs/en/sql-reference/sql-functions/string-functions/char_length.md
index e7478893c9..fbba1480c6 100644
--- a/docs/en/sql-reference/sql-functions/string-functions/char_length.md
+++ b/docs/en/sql-reference/sql-functions/string-functions/char_length.md
@@ -31,7 +31,7 @@ under the License.
 'INT char_length (VARCHAR str)'
 
 
-Returns the length of the string and the number of characters returned for multi-byte characters. For example, five two-byte width words return a length of 5, only utf8 encodeing is support at current version.
+Returns the length of the string, and the number of characters returned for multi-byte characters. For example, five two-byte width words return a length of 5, only utf8 encoding is support at the current version. `character_length` is the alias for this function.
 
 ## example
 
@@ -52,4 +52,4 @@ mysql> select char_length("中国");
 +-----------------------+
 ```
 ## keyword
-CHAR_LENGTH
+CHAR_LENGTH, CHARACTER_LENGTH
diff --git a/docs/zh-CN/sql-reference/sql-functions/string-functions/char_length.md b/docs/zh-CN/sql-reference/sql-functions/string-functions/char_length.md
index 9bd3c1f56b..fe3cf37bd7 100644
--- a/docs/zh-CN/sql-reference/sql-functions/string-functions/char_length.md
+++ b/docs/zh-CN/sql-reference/sql-functions/string-functions/char_length.md
@@ -31,7 +31,7 @@ under the License.
 `INT char_length(VARCHAR str)`
 
 
-返回字符串的长度，对于多字节字符，返回字符数, 目前仅支持utf8 编码。
+返回字符串的长度，对于多字节字符，返回字符数, 目前仅支持utf8 编码。这个函数还有一个别名 `character_length`。
 
 ## example
 
@@ -51,4 +51,4 @@ mysql> select char_length("中国");
 +-----------------------+
 ```
 ##keyword
-CHAR_LENGTH
+CHAR_LENGTH, CHARACTER_LENGTH