1、
子查詢優化法
先找出第一條資料，然後大於等於這條資料的id就是要獲取的資料
缺點：資料必須是連續的，可以說不能有where條件，where條件會篩選資料，導致資料失去連續性。
實驗下：
**如下
複製**
mysql> set profiling=1;
query ok, 0 rows affected (0.00 sec)
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 profilesg
*************************** 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
從結果中可以得知，當偏移1000以上使用子查詢法可以有效的提高效能。
2、join查詢法（實質轉化為對id查詢）
總資料有500萬左右
以下例子：當使用 select * from wl_tagindex where byname='f' order by id limit 300000,10 執行時間是 3.21s
優化後：
select * from (
select id from wl_tagindex
where byname='f' order by id limit 300000,10
) aleft join wl_tagindex b on a.id=b.id
執行時間為 0.11s 速度明顯提公升
這裡需要說明的是，我這裡用到的字段是 byname ,id 需要把這兩個欄位做復合索引，否則的話效果提公升不明顯。
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