COUNT SHARDING RULE
Description
The COUNT SHARDING RULE syntax is used to query the number of sharding rules for specified database.
Syntax
CountShardingRule::=
'COUNT' 'SHARDING' 'RULE' ('FROM' databaseName)?
databaseName ::=
identifierSupplement
- When
databaseNameis not specified, the default is the currently usedDATABASE. IfDATABASEis not used,No database selectedwill be prompted.
Return value description
| Column | Description |
|---|---|
| rule_name | rule type |
| database | the database to which the rule belongs |
| count | the number of the rule |
Example
- Query the number of sharding rules for specified database.
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)- Query the number of sharding rules for current database.
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)Reserved word
COUNT, SHARDING, RULE, FROM