请问oracle和mysql性能问题,怎么这么大差距
mysql> show tables;
+------------------+
| Tables_in_cmname |
+------------------+
| cmnum |
| emp |
| name |
+------------------+
3 rows in set (0.00 sec)
mysql> desc name;
+---------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+--------------+------+-----+---------+----------------+
| ID | int(11) | | PRI | NULL | auto_increment |
| name | varchar(200) | | | | |
| tel | varchar(200) | | | | |
| bumen | varchar(200) | | | | |
| gangwei | varchar(200) | | | | |
+---------+--------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)
mysql> desc cmnum;
+----------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------------+-------------+------+-----+---------+-------+
| userid | varchar(20) | YES | | NULL | |
| custid | varchar(20) | YES | | NULL | |
| acctid | varchar(20) | YES | | NULL | |
| svcnum | varchar(20) | YES | | NULL | |
| brand | varchar(20) | YES | | NULL | |
| devnum | varchar(20) | YES | | NULL | |
| stopflag | varchar(20) | YES | | NULL | |
| billingcycleid | varchar(20) | YES | | NULL | |
| stop_type | varchar(20) | YES | | NULL | |
| busisit | varchar(20) | YES | | NULL | |
| innetdate | varchar(20) | YES | | NULL | |
| subsvc | varchar(20) | YES | | NULL | |
| svcplancode | varchar(20) | YES | | NULL | |
| busistat | varchar(20) | YES | | NULL | |
| desc1 | varchar(20) | YES | | NULL | |
| addflag | varchar(20) | YES | | NULL | |
| addacptdate | varchar(20) | YES | | NULL | |
| creditlvl | varchar(20) | YES | | NULL | |
| firstcalldate | varchar(20) | YES | | NULL | |
| multacctflag | varchar(20) | YES | | NULL | |
| status | varchar(20) | YES | | NULL | |
+----------------+-------------+------+-----+---------+-------+
21 rows in set (0.00 sec)
mysql>select * from name,cmnum where name.tel=cmnum.svcnum;
.............
运行后windows死机。而同样的表结构在oracle中却在10s左右运算出来了。
请指教这是什么原因