COUNT READWRITE_SPLITTING RULE
描述
COUNT READWRITE_SPLITTING RULE 语法用于查询指定逻辑库中的读写分离规则数量。
语法
CountReadwriteSplittingRule::=
'COUNT' 'READWRITE_SPLITTING' 'RULE' ('FROM' databaseName)?
databaseName ::=
identifier补充说明
- 未指定
databaseName时，默认是当前使用的DATABASE。 如果也未使用DATABASE则会提示No database selected。
返回值说明
| 列 | 说明 |
|---|---|
| rule_name | 规则类型 |
| database | 规则所属逻辑库 |
| count | 规则数量 |
示例
- 查询指定逻辑库中的读写分离规则数量
COUNT READWRITE_SPLITTING RULE FROM readwrite_splitting_db;mysql> COUNT READWRITE_SPLITTING RULE FROM readwrite_splitting_db;
+---------------------+---------------------------+-------+
| rule_name | database | count |
+---------------------+---------------------------+-------+
| readwrite_splitting | readwrite_splitting_db | 1 |
+---------------------+---------------------------+-------+
1 row in set (0.02 sec)- 查询当前逻辑库中的读写分离规则数量
COUNT READWRITE_SPLITTING RULE;mysql> COUNT READWRITE_SPLITTING RULE;
+---------------------+---------------------------+-------+
| rule_name | database | count |
+---------------------+---------------------------+-------+
| readwrite_splitting | readwrite_splitting_db | 1 |
+---------------------+---------------------------+-------+
1 row in set (0.00 sec)保留字
COUNT、READWRITE_SPLITTING、RULE、FROM