[Feature]Support functions of json_array, json_object, json_quote (#6504)

docs/en/sql-reference/sql-functions/string-functions/json_array.md

@@ -0,0 +1,70 @@
+---
+{
+    "title": "json_array",
+    "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.
+-->
+
+# json_array
+## Description
+### Syntax
+
+`VARCHAR json_array(VARCHAR,...)`
+
+
+Generate a json array containing the specified values, return empty if no values
+
+## example
+
+```
+MySQL> select json_array();
++--------------+
+| json_array() |
++--------------+
+| []           |
++--------------+
+
+MySQL> select json_array(null);
++--------------------+
+| json_array('NULL') |
++--------------------+
+| [NULL]             |
++--------------------+
+
+
+MySQL> SELECT json_array(1, "abc", NULL, TRUE, CURTIME());
++-----------------------------------------------+
+| json_array(1, 'abc', 'NULL', TRUE, curtime()) |
++-----------------------------------------------+
+| [1, "abc", NULL, TRUE, "10:41:15"]            |
++-----------------------------------------------+
+
+
+MySQL> select json_array("a", null, "c");
++------------------------------+
+| json_array('a', 'NULL', 'c') |
++------------------------------+
+| ["a", NULL, "c"]             |
++------------------------------+
+```
+## keyword
+json_array