MySQL相当于Sybase ASE命令？

相当于sybase ASE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Sybase ASE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)