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                合規國際互聯網加速 OSASE為企業客戶提供高速穩定SD-WAN國際加速解決方案。 廣告
                常規的分頁寫法如下 ```sql select id,title,type from tablename order by id limit 100,10; ``` 經測試,如果數據量比較大的時候,如近百萬的時候。查詢語句就變成了如下 ```sql select id,title,subtitle from tablename order by id limit 990000,10; ``` 這時候查詢就耗時較長了。 主鍵id為連續數據,網上推薦的方法一般是子查詢和between(,初測BETWEEN速度更快) 寫法如下: ```sql select id,title,subtitle from tablename id >=(select id from tablename limit 1000000,1) limit 10; select id,title,subtitle from tablename BETWEEN 1000000 AND 1000010; select id,title,subtitle from tablename where id>= 1000000 AND id<=1000010; ``` 主鍵為非連續數據。一般是先查出ids 然后用in查詢較快 ```sql select id.title,subtitle from tablename in(100000,9999999,8548685,100); ``` 看到segmentfault上一個問答, > 至于優化查詢,本質上說,先要優化數據結構,仔細想想你是否必須非要用兩個表,一個行不行。還有你對數據庫內置函數的了解程度,比如left(), right(), substring(), substring_index()。還有 mid(), substr()。不要動不動就LIKE等等,主要還是多寫,根據實際應用場景來做出最優判斷。 順便一說MYSQL配置本身也可以進行很多優化,比如query_cache等等 看來應該抽時間,再次好好研讀一下mysql的知識了,基礎不牢,地動山搖啊!
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                              哎呀哎呀视频在线观看