问题描述
我有一个jquery滚子/滚动器，显示从我的有用的提示数据库表查询返回的记录片段。我想保持滚动约15记录，但不总是前15个记录。
I've got a jquery roller/scroller that displays snippets of records returned from my 'Helpful Hints' database table query. I want to keep the scroller to about 15 records but not always the first 15 records.
编写一个查询更有效率：
Is it more efficient to write a query like:
SELECT *
FROM table
ORDER BY RAND()
LIMIT n
其中返回一个随机结果或返回整个查询，并让我的ColdFusion组件提供一个随机数的查询结果？
Which returns a random result or do I return the whole query and have my ColdFusion component serve up a random number of the query result?
我的滚动器的未来将包括
The future of my scroller will include random records from my 'Items for Sale' table as well, so I need to keep that in mind.
推荐答案
我同意bemace返回一个不会用于Coldfusion的大型结果集是浪费了无法补偿的资源。
I agree with bemace that returning a large result set of values that won't be used to Coldfusion is a waste of resources that can never be recouped.
但是要小心使用（），您应该。
But be careful about using MySQL's RAND() function for ordering - once you're over 100,000 records, it doesn't scale well (see graph), and you should look at using alternatives.
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