MySQL PHP 如何分批量的从数据库循环读取数据？

Question

假如每次从数据库读取五条，该怎么一直让程序循环下去，直到全都循环完成。
加个

$a = true;
//然后用while循环
//在数据库里设计个字段，为判断有没有取出来过这条数据的字段，默认为没取出来过
//然后用foreach把每次取出来的每条数据都标记为已取出过，直到所有数据都被标记为已取出过来，循环停止。

这样的逻辑对吗？

Answer 1

<?php

$read  =  ture;
$limit =  0;
while($read)
{    

    $sql = "select id,name from table limit {$limit},5";
    $data = $db->select($sql); 
    //todo 你的业务逻辑
    
    if(!data)
    {    
        $read = false;
        break;数据为空,直接停止了循环
    }
   
    $limit += 5;每次获取后面5条,直至数据查询为空.

}

Answer 2

$id = 0;
while(true){
   $arr = $db->query('select id,name from users where id>'.$id.' limit 5');
   if(count($arr) == 0) {
     break;
   }
   // 处理逻辑 
   
  if(count($arr) < 5) {
     break;
   }
   $id = $arr[4]['id']; // 取最后一个id
}

Answer 3

你用limit呀。然后记录id，直到id大于maxid不就可以了么???

Answer 4

可以用分页查询的原理啊。。

$count = '100';//总条数
$strip = 0;
$num = $count/5;//循环多少次
for($i=1;$i<=$num;$i++)
{
 $sql = "select * from `table` order by id limit ".$strip.",5";
 $strip += 5;
}

Answer 5

最好for循环里面sleep下，让cpu休息一下

Answer 6

我在想，用foreach while循环，和一次性查能有多少性能差异？ 多次查询数据库，不如一次查出来？

Answer 7

I will suggest you using a Loop when enters the name. Make sure to use ForEach Loop. Moreover let me tell you that you can Check Chase Verify.

Answer 8

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Answer 9

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Answer 10

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Answer 11

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Answer 12

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