MYSQL OR vs IN性能 [英] MYSQL OR vs IN performance

问题描述

我想知道以下内容在性能方面是否有差异

I am wondering if there is any difference in regards to performance between the following

SELECT ... FROM ... WHERE someFIELD IN(1,2,3,4)

SELECT ... FROM ... WHERE someFIELD between  0 AND 5

SELECT ... FROM ... WHERE someFIELD = 1 OR someFIELD = 2 OR someFIELD = 3 ... 

或者MySQL将以与编译器优化代码相同的方式优化SQL?

or will MySQL optimize the SQL in the same way compilers will optimize code ?

由于注释中所述的原因，将AND更改为OR.

Changed the AND's to OR's for the reason stated in the comments.

推荐答案

我需要确定这一点，因此我对这两种方法进行了基准测试.我始终发现IN比使用OR快得多.

I needed to know this for sure, so I benchmarked both methods. I consistenly found IN to be much faster than using OR.

不要相信给出意见的人，科学就是测试和证据.

Do not believe people who give their "opinion", science is all about testing and evidence.

我运行了1000倍等效查询的循环(为了保持一致，我使用了sql_no_cache):

I ran a loop of 1000x the equivalent queries (for consistency, I used sql_no_cache):

IN:2.34969592094s

IN: 2.34969592094s

OR:5.83781504631s

OR: 5.83781504631s

更新:
(我没有6年前的原始测试源代码，尽管它返回的结果与此测试范围相同)

在请求一些示例代码进行测试时，这是最简单的用例.使用Eloquent简化语法，等效的原始SQL执行相同的操作.

In request for some sample code to test this, here is the simplest possible use case. Using Eloquent for syntax simplicity, raw SQL equivalent executes the same.

$t = microtime(true); 
for($i=0; $i<10000; $i++):
$q = DB::table('users')->where('id',1)
    ->orWhere('id',2)
    ->orWhere('id',3)
    ->orWhere('id',4)
    ->orWhere('id',5)
    ->orWhere('id',6)
    ->orWhere('id',7)
    ->orWhere('id',8)
    ->orWhere('id',9)
    ->orWhere('id',10)
    ->orWhere('id',11)
    ->orWhere('id',12)
    ->orWhere('id',13)
    ->orWhere('id',14)
    ->orWhere('id',15)
    ->orWhere('id',16)
    ->orWhere('id',17)
    ->orWhere('id',18)
    ->orWhere('id',19)
    ->orWhere('id',20)->get();
endfor;
$t2 = microtime(true); 
echo $t."\n".$t2."\n".($t2-$t)."\n";

1482080514.3635
1482080517.3713
3.0078368186951

1482080514.3635
1482080517.3713
3.0078368186951

$t = microtime(true); 
for($i=0; $i<10000; $i++): 
$q = DB::table('users')->whereIn('id',[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20])->get(); 
endfor; 
$t2 = microtime(true); 
echo $t."\n".$t2."\n".($t2-$t)."\n";

1482080534.0185
1482080536.178
2.1595389842987

1482080534.0185
1482080536.178
2.1595389842987

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