MySQL相当于Sybase ASE命令？
相当于sybaseASE命令的MySQL是EXPLAIN关键字。让我们首先创建一个表-
mysql> create table DemoTable1531 -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(20) -> ); mysql> create index Name_index1 on DemoTable1531(StudentName); Records: 0 Duplicates: 0 Warnings: 0
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable1531(StudentName) values('Chris');
mysql> insert into DemoTable1531(StudentName) values('Robert');
mysql> insert into DemoTable1531(StudentName) values('David');
mysql> insert into DemoTable1531(StudentName) values('Mike');
mysql> insert into DemoTable1531(StudentName) values('Carol');使用select语句显示表中的所有记录-
mysql> select * from DemoTable1531;
这将产生以下输出-
+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | 5 | Carol | | 1 | Chris | | 3 | David | | 4 | Mike | | 2 | Robert | +-----------+-------------+ 5 rows in set (0.00 sec)
以下是实现与SybaseASE等效的MySQL的查询-
mysql> EXPLAIN select * from DemoTable1531 where StudentName='Mike';
这将产生以下输出-
+----+-------------+---------------+------------+------+---------------+-------------+---------+-------+------+----------+-------------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra | +----+-------------+---------------+------------+------+---------------+-------------+---------+-------+------+----------+-------------+ | 1 | SIMPLE | DemoTable1531 | NULL | ref | Name_index1 | Name_index1 | 63 | const | 1 | 100.00 | Using index | +----+-------------+---------------+------------+------+---------------+-------------+---------+-------+------+----------+-------------+ 1 row in set, 1 warning (0.00 sec)