mysql优化limit查询语句的5个方法

mysql的分页比较简单，只需要limit offset,length就可以获取数据了，但是当offset和length比较大的时候，mysql明显性能下降

1.子查询优化法

先找出第一条数据，然后大于等于这条数据的id就是要获取的数据
缺点：数据必须是连续的，可以说不能有where条件，where条件会筛选数据，导致数据失去连续性，具体方法请看下面的查询实例：

mysql> select count(*) from Member;
+----------+
| count(*) |
+----------+
|   169566 |
+----------+
1 row in set (0.00 sec)

mysql> pager grep !~-
PAGER set to 'grep !~-'

mysql> select * from Member limit 10, 100;
100 rows in set (0.00 sec)

mysql> select * from Member where MemberID >= (select MemberID from Member limit 10,1) limit 100;
100 rows in set (0.00 sec)

mysql> select * from Member limit 1000, 100;
100 rows in set (0.01 sec)

mysql> select * from Member where MemberID >= (select MemberID from Member limit 1000,1) limit 100;
100 rows in set (0.00 sec)

mysql> select * from Member limit 100000, 100;
100 rows in set (0.10 sec)

mysql> select * from Member where MemberID >= (select MemberID from Member limit 100000,1) limit 100;
100 rows in set (0.02 sec)

mysql> nopager
PAGER set to stdout

mysql> show profiles/G
*************************** 1. row ***************************
Query_ID: 1
Duration: 0.00003300
   Query: select count(*) from Member

*************************** 2. row ***************************
Query_ID: 2
Duration: 0.00167000
   Query: select * from Member limit 10, 100
*************************** 3. row ***************************
Query_ID: 3
Duration: 0.00112400
   Query: select * from Member where MemberID >= (select MemberID from Member limit 10,1) limit 100

*************************** 4. row ***************************
Query_ID: 4
Duration: 0.00263200
   Query: select * from Member limit 1000, 100
*************************** 5. row ***************************
Query_ID: 5
Duration: 0.00134000
   Query: select * from Member where MemberID >= (select MemberID from Member limit 1000,1) limit 100

*************************** 6. row ***************************
Query_ID: 6
Duration: 0.09956700
   Query: select * from Member limit 100000, 100
*************************** 7. row ***************************
Query_ID: 7
Duration: 0.02447700
   Query: select * from Member where MemberID >= (select MemberID from Member limit 100000,1) limit 100