从具有百万条目的mysql数据库中获取少量记录-Fetchingfewrecordsfrommysqldatabasehavingmillionentries

1  

I am assuming that your ids are integer. Maybe you are getting this list of Ids from some other sources so that a join on mysql side is not desired solution. If yes, then find the maximum and minimum id present in your 500 Ids list. You can do this in php side. When you have the max and min value, then query mysql db with a where clause

我假设你的id是整数。也许你从其他一些来源获得这个ID列表,以便在mysql端加入不是所需的解决方案。如果是,则查找500 Ids列表中的最大和最小ID。你可以在php端做到这一点。当你有最大值和最小值时,然后使用where子句查询mysql db

select ...
  from table_name
  where min_id <= id and id <= max_id

id is the primary key so the advantage is that it is already indexed.

id是主键,因此优点是它已经被索引。

1  

I have done this in the past, I am not sure that my method is the most efficient.

我过去做过这个,我不确定我的方法是最有效的。

I create a string out of the ids: where id = a or id = b or id = c ...

我用ids创建一个字符串:其中id = a或id = b或id = c ...

then I add the select statement in front of it, and do a fetchall.

然后我在它前面添加select语句,然后做一个fetchall。

0  

My guess is that you're getting these user IDs from another table and that you are storing them in an array. If this is correct, then you should change the query that fetches these user IDs so that it uses a join instead.

我的猜测是你从另一个表中获取这些用户ID,并将它们存储在一个数组中。如果这是正确的,那么您应该更改获取这些用户ID的查询,以便它使用连接。

-1  

Joins will help you there, because IN() is not a good programming practice. You can learn about joins here : http://mysqljoin.com/

联接将帮助你,因为IN()不是一个好的编程实践。您可以在这里了解加入:http://mysqljoin.com/