Batch fix broken external links (#6626) (#6632)

functions-and-operators/aggregate-group-by-functions.md

@@ -8,22 +8,22 @@ title: GROUP BY 聚合函数
 
 ## TiDB 支持的聚合函数
 
-TiDB 支持的 MySQL GROUP BY 聚合函数如下所示：
+TiDB 支持的 MySQL `GROUP BY` 聚合函数如下所示：
 
 | 函数名    | 功能描述              |
 |:---------|:--------------------|
-| [`COUNT()`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_count)                   | 返回检索到的行的数目|
-| [`COUNT(DISTINCT)`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_count-distinct)  | 返回不同值的数目 |
-| [`SUM()`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_sum)                       | 返回和         |
-| [`AVG()`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_avg)                       | 返回平均值     |
-| [`MAX()`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_max)                       | 返回最大值     |
-| [`MIN()`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_min)                       | 返回最小值     |
-| [`GROUP_CONCAT()`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_group-concat)     | 返回连接的字符串  |
-| [`VARIANCE()`，`VAR_POP()`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_var-pop) | 返回总体标准方差 |
+| [`COUNT()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_count)                   | 返回检索到的行的数目|
+| [`COUNT(DISTINCT)`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_count-distinct)  | 返回不同值的数目 |
+| [`SUM()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_sum)                       | 返回和         |
+| [`AVG()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_avg)                       | 返回平均值     |
+| [`MAX()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_max)                       | 返回最大值     |
+| [`MIN()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_min)                       | 返回最小值     |
+| [`GROUP_CONCAT()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_group-concat)     | 返回连接的字符串  |
+| [`VARIANCE()`，`VAR_POP()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_var-pop) | 返回总体标准方差 |
 | [`STD()`，`STDDEV()`，`STDDEV_POP`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_std) | 返回总体标准差 |
 | [`VAR_SAMP()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_var-samp) | 返回采样方差 |
 | [`STDDEV_SAMP()`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_stddev-samp) | 返回采样标准方差 |
-| [`JSON_OBJECTAGG(key, value)`](https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_json-objectagg) | 将结果集返回为单个含 (key, value) 键值对的 JSON object |
+| [`JSON_OBJECTAGG(key, value)`](https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_json-objectagg) | 将结果集返回为单个含 (key, value) 键值对的 JSON object |
 
 > **注意：**
 >

functions-and-operators/expressions-pushed-down.md

@@ -149,23 +149,43 @@ tidb> explain select * from t where a < 2 and a > 2;
 | IS FALSE | isfalse |
 
 [json_extract]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-extract
+
 [json_short_extract]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#operator_json-column-path
+
 [json_short_extract_unquote]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#operator_json-inline-path
+
 [json_unquote]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-unquote
+
 [json_type]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-type
+
 [json_set]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-set
+
 [json_insert]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-insert
+
 [json_replace]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-replace
+
 [json_remove]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-remove
+
 [json_merge]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-merge
+
 [json_merge_preserve]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-merge-preserve
+
 [json_object]: https://dev.mysql.com/doc/refman/5.7/en/json-creation-functions.html#function_json-object
+
 [json_array]: https://dev.mysql.com/doc/refman/5.7/en/json-creation-functions.html#function_json-array
+
 [json_keys]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-keys
+
 [json_length]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-length
+
 [json_valid]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-valid
+
 [json_quote]: https://dev.mysql.com/doc/refman/5.7/en/json-creation-functions.html#function_json-quote
+
 [json_contains]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-contains
+
 [json_contains_path]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-contains-path
-[json_arrayagg]: https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_json-arrayagg
+
+[json_arrayagg]:https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_json-arrayagg
+
 [json_depth]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-depth

functions-and-operators/json-functions.md

@@ -82,27 +82,51 @@ TiDB 暂未支持以下 JSON 函数。相关进展参见 [TiDB #7546](https://gi
 * [JSON Data Type](/data-type-json.md)
 
 [json_extract]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-extract
+
 [json_short_extract]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#operator_json-column-path
+
 [json_short_extract_unquote]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#operator_json-inline-path
+
 [json_unquote]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-unquote
+
 [json_type]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-type
+
 [json_set]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-set
+
 [json_insert]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-insert
+
 [json_replace]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-replace
+
 [json_remove]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-remove
+
 [json_merge]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-merge
+
 [json_merge_preserve]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-merge-preserve
+
 [json_object]: https://dev.mysql.com/doc/refman/5.7/en/json-creation-functions.html#function_json-object
+
 [json_array]: https://dev.mysql.com/doc/refman/5.7/en/json-creation-functions.html#function_json-array
+
 [json_keys]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-keys
+
 [json_length]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-length
+
 [json_valid]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-valid
+
 [json_quote]: https://dev.mysql.com/doc/refman/5.7/en/json-creation-functions.html#function_json-quote
+
 [json_contains]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-contains
+
 [json_contains_path]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-contains-path
-[json_arrayagg]: https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_json-arrayagg
+
+[json_arrayagg]: https://dev.mysql.com/doc/refman/5.7/en/aggregate-functions.html#function_json-arrayagg
+
 [json_depth]: https://dev.mysql.com/doc/refman/5.7/en/json-attribute-functions.html#function_json-depth
+
 [json_search]: https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-search
+
 [json_append]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-append
+
 [json_array_append]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-array-append
+
 [json_array_insert]: https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-array-insert