从查询中获取10行

问题描述：

我有它由连接的并且具有约30,000的记录的输出的查询。我想从这些记录的10个随机行，而不使用SQL命令ORDER BY兰特（）。

I have a query which consists of joins and has an output of about 30,000+ records. I would like to get 10 random rows from these records without using SQL command ORDER BY rand().

我试图通过循环记录，并把它们放在一个数组和随机（获得洗牌后，10月1日）他们，但它需要大约8-12秒钟生成。我想不惜一切代价来减少这种处理时间。

I tried looping through the records and put them in an array and shuffle (get the 1st 10 after shuffle) them but it takes about 8-12 seconds to generate. I would like to reduce this processing time at all cost.

我将如何做到这一点？

How will I accomplish this?

答

好吧，如果你不希望使用RAND（）做一个更快的选择仅仅是ID列的第一个，然后只选择你想要的10行

Ok if you don't want to use RAND() do a much faster select of just the id column first then select only the 10 rows you want

选择ID添加到$ idarray

SELECT ID FROM表

随机播放和切片$ idarray

洗牌（$ idarray）;

$ IDS = array_slice（$ idarray，0,10）;

选择完整的行

$ SQL =SELECT ... WHERE ID IN（.implode（''，$ idarray）。）;

Select the IDs into $idarray
SELECT id FROM table
Shuffle and slice $idarray
shuffle($idarray);
$ids=array_slice($idarray,0,10);
Select the complete rows
$sql="SELECT ... WHERE id IN (".implode(', ', $idarray).")";

编辑：这肯定是比使用ORDER BY RAND（）

This is certainly much faster than using ORDER BY RAND()!

从查询中获取10行

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