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        哪個最快?SELECT SQL_CALC_FOUND_ROWS FROM `table`,或 SE

        Which is fastest? SELECT SQL_CALC_FOUND_ROWS FROM `table`, or SELECT COUNT(*)(哪個最快?SELECT SQL_CALC_FOUND_ROWS FROM `table`,或 SELECT COUNT(*))

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                  本文介紹了哪個最快?SELECT SQL_CALC_FOUND_ROWS FROM `table`,或 SELECT COUNT(*)的處理方法,對大家解決問題具有一定的參考價值,需要的朋友們下面隨著小編來一起學習吧!

                  問題描述

                  當你限制一個SQL查詢返回的行數時,通常用于分頁,有兩種方法可以確定總記錄數:

                  When you limit the number of rows to be returned by a SQL query, usually used in paging, there are two methods to determine the total number of records:

                  在原SELECT中包含SQL_CALC_FOUND_ROWS選項,然后通過運行SELECT FOUND_ROWS()得到總行數:>

                  Include the SQL_CALC_FOUND_ROWS option in the original SELECT, and then get the total number of rows by running SELECT FOUND_ROWS():

                  SELECT SQL_CALC_FOUND_ROWS * FROM table WHERE id > 100 LIMIT 10;
                  SELECT FOUND_ROWS();  
                  

                  方法二

                  正常運行查詢,然后通過運行SELECT COUNT(*)

                  SELECT * FROM table WHERE id > 100 LIMIT 10;
                  SELECT COUNT(*) FROM table WHERE id > 100;  
                  

                  哪種方法最好/最快?

                  推薦答案

                  視情況而定.請參閱有關此主題的 MySQL 性能博客文章:要SQL_CALC_FOUND_ROWS 還是不SQL_CALC_FOUND_ROWS?

                  It depends. See the MySQL Performance Blog post on this subject: To SQL_CALC_FOUND_ROWS or not to SQL_CALC_FOUND_ROWS?

                  只是一個簡短的總結:彼得說這取決于您的索引和其他因素.該帖子的許多評論似乎都說 SQL_CALC_FOUND_ROWS 幾乎總是比運行兩個查詢慢 - 有時最多慢 10 倍.

                  Just a quick summary: Peter says that it depends on your indexes and other factors. Many of the comments to the post seem to say that SQL_CALC_FOUND_ROWS is almost always slower - sometimes up to 10x slower - than running two queries.

                  這篇關于哪個最快?SELECT SQL_CALC_FOUND_ROWS FROM `table`,或 SELECT COUNT(*)的文章就介紹到這了,希望我們推薦的答案對大家有所幫助,也希望大家多多支持html5模板網!

                  【網站聲明】本站部分內容來源于互聯網,旨在幫助大家更快的解決問題,如果有圖片或者內容侵犯了您的權益,請聯系我們刪除處理,感謝您的支持!

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