使用LIMIT 0、20进行无限滚动-如何限制总结果数？

Question

I have a query:

 select * from table where id is not null order by desc LIMIT :start, :limit

the start and limit are there for the ajax infinite scroll / pagination to work

How can I limit the total results if im using limit already for the pagination?

I need a query similar to below:

select * from table where id is not null order by desc LIMIT :start, :limit LIMIT 5000

Answer 1

You can calculate this without the query. If you don't want more than 5000 results, this should work:

if (($start + $limit) <= 5000) {
    // Do query
}
else {
    // Don't do query, maximum limit reached
}

Answer 2

You can create a view in your database wih the following syntax:

create view view_name as select * from table where id is not null order by desc LIMIT 5000

Then you will query the view for the ajax infinite scroll / pagination

select * from view_name where id is not null order by desc LIMIT :start, :limit

Note: with the view your can use a simpler query, since the view already choose the good rows (with non null id), and order them.

select * from view_name LIMIT :start, :limit