3.7 Utility Statements
3.7.1 USE
USE db_name
例:
use TESTDB;
3.7.2 EXPLAIN
EXPLAIN explainable_stmt
SELECT statement
| DELETE statement
| INSERT statement
| REPLACE statement
| UPDATE statement
注意事项:
INSERT中表不能为自增序列表
例:explain SELECT select * from a_test where id=1;
在dble中,EXPLAIN 不等价于于DESC
3.7.3 EXPLAIN2
EXPLAIN2 shardingNode=node_name sql=sql_stmt
例:
explain2 shardingNode=dn2 sql=select * from a_test where id=1;
3.7.4 DESC
{DESCRIBE | DESC} tbl_name [col_name | wild]
例:
DESC a_test id;
注意: 在dble中,EXPLAIN 不等价于于DESC