COUNT SHARDING RULE 语法用于查询指定逻辑库中的分片规则数量。
CountShardingRule::=
'COUNT' 'SHARDING' 'RULE' ('FROM' databaseName)?
databaseName ::=
identifier
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。| 列 | 说明 |
|---|---|
| rule_name | 规则类型 |
| database | 规则所属逻辑库 |
| count | 规则数量 |
COUNT SHARDING RULE FROM sharding_db;
mysql> COUNT SHARDING RULE FROM sharding_db;
+--------------------------+----------------+-------+
| rule_name | database | count |
+--------------------------+----------------+-------+
| sharding_table | sharding_db | 2 |
| sharding_table_reference | sharding_db | 2 |
+--------------------------+----------------+-------+
2 rows in set (0.00 sec)
COUNT SHARDING RULE;
mysql> COUNT SHARDING RULE;
+--------------------------+----------------+-------+
| rule_name | database | count |
+--------------------------+----------------+-------+
| sharding_table | sharding_db | 2 |
| sharding_table_reference | sharding_db | 2 |
+--------------------------+----------------+-------+
2 rows in set (0.00 sec)
COUNT、SHARDING、RULE、FROM