简体中文(ZH-CN) English(EN) 繁体中文(ZH-TW) 日本語(JA) 한국어(KO) Melayu(MS) Français(FR) Deutsch(DE)
Home > Backend Development > PHP Tutorial > body text

mysql_num_rows VS COUNT 效率问题分析_php技巧

WBOY
Release： 2016-05-17 09:19:56
Original
794 people have browsed it

mysql_num_rows 和 count( * ) 都能统计总数,那个能好一点呢？
或者
分别什么时候用num_rows 和 count( * )呢

一个直观的对比
测试数据：
条数：139764条
数据表大小：500M

结果：
fetch_num_rows 用时：35.272329092026
count(*) 用时：0.071956872940063

如果单纯统计数量 当然是count(*)
fetch_num_rows必须遍历数据库以后才能得出 效率低于count(*)

Related labels：
count
source：php.cn
Previous article：php 获取全局变量的代码_php技巧 Next article：在php和MySql中计算时间差的方法_php技巧
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Latest Issues
function_exists() cannot determine the custom function Function test () {return true;} if (function_exists ('test')) {echo "test is function...
From 2024-04-29 11:01:01
0
2
1626
How to display the mobile version of Google Chrome Hello teacher, how can I change Google Chrome into a mobile version?
From 2024-04-23 00:22:19
0
10
1783
The child window operates the parent window, but the output does not respond. The first two sentences are executable, but the last sentence cannot be implemented.
From 2024-04-19 15:37:47
0
1
1518
There is no output in the parent window document.onclick = function(){ window.opener.document.write('I am the output of the child ...
From 2024-04-18 23:52:34
0
1
1430
Where is the courseware about CSS mind mapping? Courseware
From 2024-04-16 10:10:18
0
0
1475
Related Topics
More>
Popular Recommendations
Popular Tutorials
More>
Related Tutorials
Popular Recommendations
Latest courses
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn：Public welfare online PHP training，Help PHP learners grow quickly！