如何计算mysql查询中的行？

Question

I want to query mysql according to row number ? suppose I want to query last 10 rows , how to do this in mysql query?

Here is my mysql query, but it queries according to 6 days interval, But I need to query it according to last 10 rows instead of 6 days interval,

SELECT people_id, people_number 'people number', count(people_number) 'Occurs',
  (
   Select count(people_number) from people_history
   where people_id =  5486 and date > DATE_SUB(NOW(), INTERVAL 6 DAY)
  ) 'Total',
  count(people_number)/(
      Select count(people_number) from people_history
      where people_id = 5486 and date > DATE_SUB(NOW(), INTERVAL 6 DAY)
  )*100 'Percent'
FROM people_history
where people_id = 5486 and date > DATE_SUB(NOW(), INTERVAL 6 DAY)
group by people_id, people_number
order by Percent desc`

Answer 1

Make your query this:

SELECT * FROM people_history ORDER BY id DESC LIMIT 10

Limit allows you to limit the amount of results you get from a query. By sorting by ID you can get the last 20 results in your table.

Answer 2

LIMIT :

SELECT 
    people_id,
    people_number 'people number',
    count(people_number) 'Occurs',
    (Select 
        count(people_number) 
    from 
        people_history 
    where 
        people_id = 5486 
        and date > DATE_SUB(NOW(), INTERVAL 6 DAY)) 'Total',            
    count(people_number) / 
        (Select 
            count(people_number) 
        from 
            people_history 
        where 
            people_id = 5486 
            and date > DATE_SUB(NOW(), INTERVAL 6 DAY)) *100 'Percent' 
FROM 
    people_history 
WHERE
    people_id = 5486 
    and date > DATE_SUB(NOW(), INTERVAL 6 DAY)
GROUP BY
    people_id, people_number 
ORDER BY 
    Percent desc
LIMIT 0, 10

And you might want to rewrite that query a little.

Answer 3

反转您的ORDER，因此后10个是前10个，LIMIT减10。

Answer 4

LIMIT will restrict the number of results returned. It goes at the end of the query. Take a look at the documentation for SELECT , and go down to the LIMIT section.

For your query, if you add LIMIT 10 at the end, you will get only the 10 results you are looking for. Combine LIMIT with ORDER BY (ASC or DESC) to get the first or last results.

Answer 5

well "last" has to refer to some sort of ordering (order by .... ) statement. you always add limit N (N=10 in your case)