greatest-n-per-group

I have a cars table which contains car listings. The table structure looks something like: cars - id - title - make - year I would like a query which returns 10 cars of each make. Something equivalent to the following pseudo code: car_makes = select distinct make from cars for each make in car_makes select id, title, make from clcars where make = $make limit 10; end Here's what I've tried unsuccessfully: select id,title,make from cars where make in (select distinct make from cars) group by make; --- This returns only one record per make. select a.id,a.title,a.make from cars a left join (select

The two tables are salary_employee and employee employee_salary salary_id emp_id salary Employee emp_id | first_name | last_name | gender | email | mobile | dept_id | is_active Query to get the all employees who have nth highest salary where n =1,2,3,... any integer SELECT a.salary, b.first_name FROM employee_salary a JOIN employee b ON a.emp_id = b.emp_id WHERE a.salary = ( SELECT salary FROM employee_salary GROUP BY salary DESC LIMIT 1 OFFSET N-1 ) My Questions: 1) Is there any better and optimized way we can query this, 2) Is using LIMIT an good option 3) We have more options to calculate

What I need done is simple... but its 3am and Im probably overlooking the obvious. Im coding a simple forum. One table stores the forum titles, descriptions, etc, while the other stores the posts. In the forum listing, that shows the list of all forums, I want to grab the latest post in each forum, and display the post subject, poster and post ID, and date. Simple. The only problem is, when I join to the posts table, it joins to the first record in the table, not the last, which would denote the last post in that forum. Here is the simplified query that gets a list of forums + data for the

I am trying to select top 2 records from a database table result that looks like this SubjectId | StudentId | Levelid | total ------------------------------------------ 1 | 1 | 1 | 89 1 | 2 | 1 | 77 1 | 3 | 1 | 61 2 | 4 | 1 | 60 2 | 5 | 1 | 55 2 | 6 | 1 | 45 i tried this query SELECT rv.subjectid, rv.total, rv.Studentid, rv.levelid FROM ResultView rv LEFT JOIN ResultView rv2 ON ( rv.subjectid = rv2.subjectid AND rv.total <= rv2.total ) GROUP BY rv.subjectid, rv.total, rv.Studentid HAVING COUNT( * ) <= 2 order by rv.subjectid desc but some subjects like where missing, i even tried the

I'm looking for a way to select the most occurring value, e.g. the person who posted most for each thread; SELECT MOST_OCCURRING(user_id) FROM thread_posts GROUP BY thread_id Is there a good way to do this? If you want a count on a per thread basis, I think you can use a nested query; grouping by thread first and then by user: SELECT thread_id AS tid, (SELECT user_id FROM thread_posts WHERE thread_id = tid GROUP BY user_id ORDER BY COUNT(*) DESC LIMIT 0,1) AS topUser FROM thread_posts GROUP BY thread_id This will tabulate the occurrences of user_id per thread SELECT thread_id, user_id, COUNT(*

I asked a question about making a "greatest n per group" type query yesterday (at the time not knowing it was called "greatest n per group") except I asked how to get the least per group. The table structure was as follows: type name value ===================== 1 item1 1 1 item2 20 2 item3 0 3 item4 5 3 item5 2 3 item6 50 I received several great answers, and the most helpful one was this: SELECT t1.type, t1.name, t1.value FROM mytable t1 LEFT JOIN mytable t2 ON t1.type = t2.type AND t1.value > t2.value WHERE t2.value IS NULL The above query results in this: type name value ===================

I have this SQL query: SELECT id, COUNT(*) AS price FROM (SELECT * FROM rt WHERE somecondition) AS st JOIN tt ON st.id = tt.id GROUP BY id; Now, I want to select all rows which have the maximum price of the table. I have tried this, which unfortunately returns no row at all: SELECT id, COUNT(*) AS price FROM (SELECT * FROM rt WHERE somecondition) AS st JOIN tt ON st.id = tt.id GROUP BY id HAVING price = MAX(price); I'm somewhat lost, does anybody have any pointers? user970780 This looks fairly simple to me: select * from <table> where <column name> in( SELECT MAX(column name) FROM table ) Try