apache · morningman · Aug 7, 2021 · May 19, 2021
diff --git a/docs/.vuepress/sidebar/en.js b/docs/.vuepress/sidebar/en.js
@@ -399,6 +399,7 @@ module.exports = [
           },
           "window-function",
           "cast",
+          "digital-masking",
         ],
       },
       {

diff --git a/docs/.vuepress/sidebar/zh-CN.js b/docs/.vuepress/sidebar/zh-CN.js
@@ -404,6 +404,7 @@ module.exports = [
           },
           "window-function",
           "cast",
+          "digital-masking",
         ],
       },
       {

diff --git a/docs/en/sql-reference/sql-functions/digital-masking.md b/docs/en/sql-reference/sql-functions/digital-masking.md
@@ -0,0 +1,56 @@
+---
+{
+    "title": "DIGITAL-MASKING",
+    "language": "en"
+}
+---
+
+<!-- 
+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.
+-->
+
+# DIGITAL_MASKING
+
+## description
+
+### Syntax
+
+```
+digital_masking(digital_number)
+```
+
+Alias function, the original function is `concat(left(id,3),'****',right(id,4))`.
+
+Desensitizes the input `digital_number` and returns the result after masking desensitization.
+
+## example
+
+1. Desensitize the cell phone number
+
+    ```sql
+    mysql> select digital_masking(13812345678);
+    +------------------------------+
+    | digital_masking(13812345678) |
+    +------------------------------+
+    | 138****5678                  |
+    +------------------------------+
+    ```
+
+## keyword
+
+DIGITAL_MASKING
diff --git a/docs/en/sql-reference/sql-statements/Data Definition/create-function.md b/docs/en/sql-reference/sql-statements/Data Definition/create-function.md
@@ -25,50 +25,60 @@ under the License.
 -->
 
 # CREATE FUNCTION
-##Description
+## Description
 ### Syntax
 
 ```
-CREATE [AGGREGATE] FUNCTION function_name
-	(angry type [...])
-	RETURNS ret_type
-	[INTERMEDIATE inter_type]
-	[PROPERTIES ("key" = "value" [, ...]) ]
+CREATE [AGGREGATE] [ALIAS] FUNCTION function_name
+    (arg_type [, ...])
+    [RETURNS ret_type]
+    [INTERMEDIATE inter_type]
+    [WITH PARAMETER(param [,...]) AS origin_function]
+    [PROPERTIES ("key" = "value" [, ...]) ]
 ```
 
 ### Parameters
 
->`AGGREGATE`: If this is the case, it means that the created function is an aggregate function, otherwise it is a scalar function.
+> `AGGREGATE`: If this is the case, it means that the created function is an aggregate function.
 >
->`Function_name`: To create the name of the function, you can include the name of the database. For example: `db1.my_func'.
->
->` arg_type': The parameter type of the function is the same as the type defined at the time of table building. Variable-length parameters can be represented by `,...`. If it is a variable-length type, the type of the variable-length part of the parameters is the same as the last non-variable-length parameter type.
+> `ALIAS`: If this is the case, it means that the created function is an alias function.
+> 
+> If the above two items are not present, it means that the created function is a scalar function.
+> 
+> `Function_name`: To create the name of the function, you can include the name of the database. For example: `db1.my_func'.
 >
->`ret_type`: Function return type.
+> `arg_type`: The parameter type of the function is the same as the type defined at the time of table building. Variable-length parameters can be represented by `,...`. If it is a variable-length type, the type of the variable-length part of the parameters is the same as the last non-variable-length parameter type.
+> **NOTICE**: `ALIAS FUNCTION` variable-length parameters are not supported, and there is at least one parameter.
+> 
+> `ret_type`: Required for creating a new function. This parameter is not required if you are aliasing an existing function.
 >
->`Inter_type`: A data type used to represent the intermediate stage of an aggregate function.
+> `inter_type`: A data type used to represent the intermediate stage of an aggregate function.
+> 
+> `param`: The parameter used to represent the alias function, containing at least one.
+> 
+> `origin_function`: Used to represent the original function corresponding to the alias function.
 >
->`properties`: Used to set properties related to this function. Properties that can be set include
+> `properties`: Used to set properties related to aggregate function and scalar function. Properties that can be set include
 >
-> "Object_file": Custom function dynamic library URL path, currently only supports HTTP/HTTPS protocol, this path needs to remain valid throughout the life cycle of the function. This option is mandatory
+>           "Object_file": Custom function dynamic library URL path, currently only supports HTTP/HTTPS protocol, this path needs to remain valid throughout the life cycle of the function. This option is mandatory
 >
-> "symbol": Function signature of scalar functions for finding function entries from dynamic libraries. This option is mandatory for scalar functions
+>           "symbol": Function signature of scalar functions for finding function entries from dynamic libraries. This option is mandatory for scalar functions
 >
-> "init_fn": Initialization function signature of aggregate function. Necessary for aggregation functions
+>           "init_fn": Initialization function signature of aggregate function. Necessary for aggregation functions
 >
-> "update_fn": Update function signature of aggregate function. Necessary for aggregation functions
+>           "update_fn": Update function signature of aggregate function. Necessary for aggregation functions
 >
-> "merge_fn": Merge function signature of aggregate function. Necessary for aggregation functions
+>           "merge_fn": Merge function signature of aggregate function. Necessary for aggregation functions
 >
-> "serialize_fn": Serialized function signature of aggregate function. For aggregation functions, it is optional, and if not specified, the default serialization function will be used
+>           "serialize_fn": Serialized function signature of aggregate function. For aggregation functions, it is optional, and if not specified, the default serialization function will be used
 >
-> "finalize_fn": A function signature that aggregates functions to obtain the final result. For aggregation functions, it is optional. If not specified, the default fetch result function will be used.
+>           "finalize_fn": A function signature that aggregates functions to obtain the final result. For aggregation functions, it is optional. If not specified, the default fetch result function will be used.
 >
-> "md5": The MD5 value of the function dynamic link library, which is used to verify that the downloaded content is correct. This option is optional
+>           "md5": The MD5 value of the function dynamic link library, which is used to verify that the downloaded content is correct. This option is optional
 >
-> "prepare_fn": Function signature of the prepare function for finding the entry from the dynamic library. This option is optional for custom functions
+>           "prepare_fn": Function signature of the prepare function for finding the entry from the dynamic library. This option is optional for custom functions
 > 
-> "close_fn": Function signature of the close function for finding the entry from the dynamic library. This option is optional for custom functions
+>           "close_fn": Function signature of the close function for finding the entry from the dynamic library. This option is optional for custom functions
 
 
 This statement creates a custom function. Executing this command requires that the user have `ADMIN` privileges.
@@ -100,12 +110,29 @@ If the `function_name` contains the database name, the custom function will be c
 
 	```
 	CREATE AGGREGATE FUNCTION my_count (BIGINT) RETURNS BIGINT PROPERTIES (
-		"init_fn"= "_ZN9doris_udf6AddUdfEPNS_15FunctionContextERKNS_6IntValES4_",
-		"update_fn" = "zn9dorisudf11CountupdateepnsFunctionContexterknsIntvalepnsbigintvale",
-		"merge_fn" = "zn9dorisudf10CountMergeepnsFunctionContexterknsBigintvaleps2
-		"finalize_fn" = "zn9dorisudf13CountFinalizepnsFunctionContexterknsBigintvale",
-		"object_file" = "http://host:port/libudasample.so"
+	    "init_fn"="_ZN9doris_udf9CountInitEPNS_15FunctionContextEPNS_9BigIntValE",
+	    "update_fn"="_ZN9doris_udf11CountUpdateEPNS_15FunctionContextERKNS_6IntValEPNS_9BigIntValE",
+	    "merge_fn"="_ZN9doris_udf10CountMergeEPNS_15FunctionContextERKNS_9BigIntValEPS2_",
+	    "finalize_fn"="_ZN9doris_udf13CountFinalizeEPNS_15FunctionContextERKNS_9BigIntValE",
+	    "object_file"="http://host:port/libudasample.so"
 	);
 	```
+
+4.  Create a scalar function with variable length parameters
+
+    ```
+    CREATE FUNCTION strconcat(varchar, ...) RETURNS varchar properties (
+        "symbol" = "_ZN9doris_udf6StrConcatUdfEPNS_15FunctionContextERKNS_6IntValES4_",
+        "object_file" = "http://host:port/libmyStrConcat.so"
+    );
+    ```
+
+5. Create a custom alias function
+
+    ```
+    CREATE ALIAS FUNCTION id_masking(INT) WITH PARAMETER(id) 
+        AS CONCAT(LEFT(id, 3), '****', RIGHT(id, 4));
+    ```
+
 ## keyword
 CREATE,FUNCTION
diff --git a/docs/en/sql-reference/sql-statements/Data Definition/show-functions.md b/docs/en/sql-reference/sql-statements/Data Definition/show-functions.md
@@ -59,8 +59,14 @@ Intermediate Type: NULL
     Function Type: Aggregate
 Intermediate Type: NULL
        Properties: {"object_file":"http://host:port/libudasample.so","finalize_fn":"_ZN9doris_udf13CountFinalizeEPNS_15FunctionContextERKNS_9BigIntValE","init_fn":"_ZN9doris_udf9CountInitEPNS_15FunctionContextEPNS_9BigIntValE","merge_fn":"_ZN9doris_udf10CountMergeEPNS_15FunctionContextERKNS_9BigIntValEPS2_","md5":"37d185f80f95569e2676da3d5b5b9d2f","update_fn":"_ZN9doris_udf11CountUpdateEPNS_15FunctionContextERKNS_6IntValEPNS_9BigIntValE"}
+*************************** 3. row ***************************
+        Signature: id_masking(INT)
+      Return Type: VARCHAR
+    Function Type: Alias
+Intermediate Type: NULL
+       Properties: {"parameter":"id","origin_function":"concat(left(`id`, 3), `****`, right(`id`, 4))"}
 
-2 rows in set (0.00 sec)
+3 rows in set (0.00 sec)
 mysql> show builtin functions in testDb like 'year%';
 +---------------+
 | Function Name |

diff --git a/docs/zh-CN/sql-reference/sql-functions/digital-masking.md b/docs/zh-CN/sql-reference/sql-functions/digital-masking.md
@@ -0,0 +1,56 @@
+---
+{
+    "title": "DIGITAL-MASKING",
+    "language": "zh-CN"
+}
+---
+
+<!-- 
+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.
+-->
+
+# DIGITAL_MASKING
+
+## description
+
+### Syntax
+
+```
+digital_masking(digital_number)
+```
+
+别名函数，原始函数为 `concat(left(id,3),'****',right(id,4))`。
+
+将输入的 `digital_number` 进行脱敏处理，返回遮盖脱敏后的结果。
+
+## example
+
+1. 将手机号码进行脱敏处理
+
+    ```sql
+    mysql> select digital_masking(13812345678);
+    +------------------------------+
+    | digital_masking(13812345678) |
+    +------------------------------+
+    | 138****5678                  |
+    +------------------------------+
+    ```
+
+## keyword
+
+DIGITAL_MASKING
diff --git a/docs/zh-CN/sql-reference/sql-statements/Data Definition/create-function.md b/docs/zh-CN/sql-reference/sql-statements/Data Definition/create-function.md
@@ -25,30 +25,40 @@ under the License.
 -->
 
 # CREATE FUNCTION
-## description
+## Description
 ### Syntax
 
 ```
-CREATE [AGGREGATE] FUNCTION function_name
+CREATE [AGGREGATE] [ALIAS] FUNCTION function_name
     (arg_type [, ...])
-    RETURNS ret_type
+    [RETURNS ret_type]
     [INTERMEDIATE inter_type]
+    [WITH PARAMETER(param [,...]) AS origin_function]
     [PROPERTIES ("key" = "value" [, ...]) ]
 ```
 
 ### Parameters
 
-> `AGGREGATE`: 如果有此项，表示的是创建的函数是一个聚合函数，否则创建的是一个标量函数。
->
+> `AGGREGATE`: 如果有此项，表示的是创建的函数是一个聚合函数。
+> 
+> `ALIAS`：如果有此项，表示的是创建的函数是一个别名函数。
+> 
+> 如果没有上述两项，表示创建的函数是一个标量函数
+> 
 > `function_name`: 要创建函数的名字, 可以包含数据库的名字。比如：`db1.my_func`。
 >
 > `arg_type`: 函数的参数类型，与建表时定义的类型一致。变长参数时可以使用`, ...`来表示，如果是变长类型，那么变长部分参数的类型与最后一个非变长参数类型一致。
+> **注意**：`ALIAS FUNCTION` 不支持变长参数，且至少有一个参数。
 > 
-> `ret_type`: 函数返回类型。
+> `ret_type`: 对创建新的函数来说，是必填项。如果是给已有函数取别名则可不用填写该参数。
 > 
 > `inter_type`: 用于表示聚合函数中间阶段的数据类型。
 > 
-> `properties`: 用于设定此函数相关属性，能够设置的属性包括
+> `param`：用于表示别名函数的参数，至少包含一个。
+> 
+> `origin_function`：用于表示别名函数对应的原始函数。
+> 
+> `properties`: 用于设定聚合函数和标量函数相关属性，能够设置的属性包括
 >       
 >           "object_file": 自定义函数动态库的URL路径，当前只支持 HTTP/HTTPS 协议，此路径需要在函数整个生命周期内保持有效。此选项为必选项
 >
@@ -97,7 +107,7 @@ CREATE [AGGREGATE] FUNCTION function_name
 	);
 	```
 
-2. 创建一个自定义聚合函数
+3. 创建一个自定义聚合函数
 
 	```
 	CREATE AGGREGATE FUNCTION my_count (BIGINT) RETURNS BIGINT PROPERTIES (
@@ -109,14 +119,21 @@ CREATE [AGGREGATE] FUNCTION function_name
 	);
 	```
 
-3. 创建一个变长参数的标量函数
+4. 创建一个变长参数的标量函数
+
+    ```
+    CREATE FUNCTION strconcat(varchar, ...) RETURNS varchar properties (
+        "symbol" = "_ZN9doris_udf6StrConcatUdfEPNS_15FunctionContextERKNS_6IntValES4_",
+        "object_file" = "http://host:port/libmyStrConcat.so"
+    );
+    ```
+
+5. 创建一个自定义别名函数
 
-       ```
-       CREATE FUNCTION strconcat(varchar, ...) RETURNS varchar properties (
-           "symbol" = "_ZN9doris_udf6StrConcatUdfEPNS_15FunctionContextERKNS_6IntValES4_",
-           "object_file" = "http://host:port/libmyStrConcat.so"
-       );
-       ```
+    ```
+    CREATE ALIAS FUNCTION id_masking(INT) WITH PARAMETER(id) 
+        AS CONCAT(LEFT(id, 3), '****', RIGHT(id, 4));
+    ```
 
 ## keyword
 

diff --git a/docs/zh-CN/sql-reference/sql-statements/Data Definition/show-functions.md b/docs/zh-CN/sql-reference/sql-statements/Data Definition/show-functions.md
@@ -60,8 +60,14 @@ Intermediate Type: NULL
     Function Type: Aggregate
 Intermediate Type: NULL
        Properties: {"object_file":"http://host:port/libudasample.so","finalize_fn":"_ZN9doris_udf13CountFinalizeEPNS_15FunctionContextERKNS_9BigIntValE","init_fn":"_ZN9doris_udf9CountInitEPNS_15FunctionContextEPNS_9BigIntValE","merge_fn":"_ZN9doris_udf10CountMergeEPNS_15FunctionContextERKNS_9BigIntValEPS2_","md5":"37d185f80f95569e2676da3d5b5b9d2f","update_fn":"_ZN9doris_udf11CountUpdateEPNS_15FunctionContextERKNS_6IntValEPNS_9BigIntValE"}
+*************************** 3. row ***************************
+        Signature: id_masking(INT)
+      Return Type: VARCHAR
+    Function Type: Alias
+Intermediate Type: NULL
+       Properties: {"parameter":"id","origin_function":"concat(left(`id`, 3), `****`, right(`id`, 4))"}
 
-2 rows in set (0.00 sec)
+3 rows in set (0.00 sec)
 mysql> show builtin functions in testDb like 'year%';
 +---------------+
 | Function Name |
-Original file line number
+Diff line change
@@ Expand Up / @@ -399,6 +399,7 @@ module.exports = [ @@
               },
               "window-function",
               "cast",
+              "digital-masking",
             ],
           },
           {
@@ Expand Down @@