I'm trying to modify the following query to find the rank of a specific videoid and I'm not having much luck can anyone suggest a solution?
SELECT videoid wins/loses as win_loss,
#curRank := #curRank + 1 AS rank
FROM cb_video,
(SELECT #curRank := 0) r
ORDER BY wins/loses DESC
I tried doing a subquery like this but it fails:
SELECT rank
FROM (SELECT videoid wins/loses as win_loss,
#curRank := #curRank + 1 AS rank
FROM cb_video,
(SELECT #curRank := 0) r
ORDER BY wins/loses DESC)
WHERE videoid = 116
Also adding the videoid to the WHERE clause without a subquery just always shows the rank being the #1 position as it only returns one row:
SELECT videoid wins/loses as win_loss,
#curRank := #curRank + 1 AS rank
FROM cb_video,
(SELECT #curRank := 0) r
WHERE videoid = 116
ORDER BY wins/loses DESC
Any ideas how to limit the result to a specific ID but still retain the rank? FYI I keep two columns (wins and loses) if that helps.
SELECT a.videoid,
(SELECT COUNT(*) FROM cb_video b
WHERE a.videoid !=b.videoid
AND (b.wins/b.loses) > (a.wins/a.loses))+1 AS rank
FROM cb_video a
WHERE a.videoid = 116
Try something like this:
SELECT videoid, rank FROM (SELECT videoid, wins/loses as win_loss, #curRank := #curRank + 1 AS rank FROM cb_video, (SELECT #curRank := 0) r ORDER BY wins/loses DESC) s WHERE videoid = 116
I've tested this on simple subset created of similar table as you've described...
It returns the ONE video and its actual final Rank of the entire set...
select *
from ( SELECT
videoid,
wins,
losses,
wins/losses,
#curRank := #curRank +1 Rank
FROM
cb_video,
( select #curRank := 0 ) r
order by
wins/losses desc ) PreQuery
where
PreQuery.VideoID = 116
Related
Trying to rank positions but instead of giving (1,2,3,3,5..) when there is a tie in the 3rd position it gives (1,2,3,4,5...).. Help please
below is the code.. thanks
.............................................................................
SELECT t.*
FROM (SELECT #curRank := IF(#prev= #cur, #curRank, #curRank + 1 ) AS classPosition,student_id, #prev:=#cur, #cur:=SUM(total_marks)
FROM (SELECT m.*
FROM marks m
WHERE classform_name = ? AND term = ? AND academic_year = ? GROUP BY student_id
ORDER BY SUM(total_marks) DESC
) n CROSS JOIN
(SELECT #curRank := 0, #prev:=NULL, #cur:=NULL ) q GROUP BY student_id
) t
WHERE student_id = ?
.............................................................................
You don't need a RANK function. You can always rank rows by joining the table to itself, in which case you get to choose how the order (and rank) is determined.
I've mixing session/# variables and aggregation can be a bit unreliable, but you could simply try changing the order of your select expressions to
student_id, #cur:=SUM(total_marks), #curRank := IF(#prev= #cur, #curRank, #curRank + 1 ) AS classPosition, #prev:=#cur
If this doesn't help, I'd suggest separating your aggregation and ranking. Actually, you're already summing in the subquery, so I am not quite sure why you're not just including the sum in the results from n.
SELECT * FROM (
SELECT #curRank := IF(#prev= #cur, #curRank, #curRank + 1 ) AS classPosition, student_id, #prev:=#cur, #cur:=overall
FROM (SELECT m.*, SUM(total_marks) AS overall
FROM marks m
WHERE classform_name = ? AND term = ? AND academic_year = ?
GROUP BY student_id
ORDER BY overall DESC
) AS n
CROSS JOIN (SELECT #curRank := 0, #prev:=NULL, #cur:=NULL ) AS q
) AS completeRankings
WHERE student_id = ?
Actually, your original query should've had other issues anyway. n would have only included a single random total_marks value for each student_id; making the outer SUM kind of pointless.
Edit - This should allow position progression to "skip" later positions according to ties:
SELECT #curRank := #curRank + 1 AS counter, #prevRank := IF(#prev=#cur, #prevRank, #curRank) AS classPosition
... to omit counter from the final results, you'll have to expand out the * explicitly.
Ranks are a real pain in MySQL.
If you want the rank for a single student with these conditions, I would recommend:
SELECT 1 + COUNT(*)
FROM marks m
WHERE m.classform_name = ? AND m.term = ? AND m.academic_year = ? AND
m.total_marks >= (SELECT m2.total_marks
FROM marks m2
WHERE m2.classform_name = m.classform_name AND
m2.term = m.term
m2.academic_year = m.academic_year
m2.student_id = ?
);;
I have list of hospitals under that there are average ratings already calculated. Now I wanted to calculate rank for list of hospitals according to their average ratings from following query
SELECT name,
hospitalID,
currentAvgRating,
#curRank := #curRank + 1 AS rank
FROM hospitals h, (SELECT #curRank := 0) r
ORDER BY currentAvgRating DESC
Now above query works when I want to see all hospitals from table but when I apply WHERE clause like below then result is wrong since with this it takes row position.
SELECT name,
hospitalID,
currentAvgRating,
#curRank := #curRank + 1 AS rank
FROM hospitals h, (SELECT #curRank := 0) r where hospitalID = '453085'
ORDER BY currentAvgRating DESC
Is there any way to get correct result when we apply where clause?
If you proceed what you just found out, logically ("when there is only 1 listitem, it cannot be ordered") - you will come to the conclusion that you NEED to select ALL rows. But nothing wrong with that, you can pack them into a subselect (which isnt even an expensive one) and apply the WHERE to that:
SELECT * FROM (
SELECT name,
hospitalID,
currentAvgRating,
#curRank := #curRank + 1 AS rank
FROM hospitals h, (SELECT #curRank := 0) r
ORDER BY currentAvgRating DESC
) toplist
WHERE toplist.hospitalID = 453085
Wrap in a subquery.
SELECT * FROM (
SELECT name,
hospitalID,
currentAvgRating,
#curRank := #curRank + 1 AS rank
FROM hospitals h, (SELECT #curRank := 0) r
ORDER BY currentAvgRating DESC
)
WHERE hospitalID = '453085'
My Table gainfinal consists of three columns-countrycode, year and values. I want to select ten rows with top ten values. First, I created a rank according to values with the following Query.
SELECT countrycode, `values`,
#curRank := #curRank + 1 AS rank
FROM gainfinal CROSS JOIN
(SELECT #curRank := 0) vars
WHERE year = 2000
ORDER By `values` DESC ;
Now, I need to select the top ten rows with the highest rank. How can I do it ?
SELECT countrycode, `values`,
#curRank := #curRank + 1 AS rank
FROM gainfinal CROSS JOIN
(SELECT #curRank := 0) vars
WHERE year = 2000
ORDER By `values` DESC
LIMIT 10;
Use
LIMIT
in SQL so example:
SELECT countrycode, `values`,
#curRank := #curRank + 1 AS rank
FROM gainfinal CROSS JOIN
(SELECT #curRank := 0) vars
WHERE year = 2000
ORDER By `values` DESC
LIMIT 10
you can get 10 rows starting from row 20 using:Limit
LIMIT 10 OFFSET 20 --Equivalent to LIMIT 20, 10
You can also use your rank variable in where statement
...WHERE year = 2000 and #curRank <11;
I have a 1 table database with (in a simplified form) the following fields:
user_id(INT), ref_id(INT), points(INT), pointsgiven(BOOL/TINY_INT)
I want a query that returns the RANK of the user_id I specify based on points, given that pointsgiven is true. The kicker is, I need ties included. I can get a result set for ALL ranks if I want with the following query
SELECT
user_id, ref_id, points, pointsgiven,
CASE
WHEN #points = COALESCE(points, 0) THEN #rownum
ELSE #rownum := #rownum + 1
END AS rank,
#points := COALESCE(points, 0)
FROM users CT
JOIN
(
SELECT #rownum := 0, #points := NULL
) r
WHERE pointsgiven=TRUE ORDER BY points DESC
So, based on that, I thought I could just use that as a subquery to get a certain user_id as follows:
select * from
(
SELECT
user_id, ref_id, points, pointsgiven,
CASE
WHEN #points = COALESCE(points, 0) THEN #rownum
ELSE #rownum := #rownum + 1
END AS rank,
#points := COALESCE(points, 0)
FROM users CT
JOIN
(
SELECT #rownum := 0, #points := NULL
) r
WHERE pointsgiven=TRUE ORDER BY points DESC
) as derived WHERE user_id = 15
But this returns [BLOB - 1 B] as the rank on the correct user_id. What am I doing wrong here?
I have no idea why your query isn't working. For a single user id, though, you can use a correlated subquery:
select user_id, ref_id, points, pointsgiven,
coalesce((select count(distinct user_id)
from users u2
where u2.pointsgiven=TRUE and
u2.points > u.points
) + 1, 1) as rank
from users u
where user_id = 15;
An index on users(pointsgiven, points, user_id) should be used by the query.
To look at just one ranking, this might even be faster than your method.
I have a table which has the following two columns including others: rating, price and code. Ratings is similar to a category. I wish to generate the top 10 for each rating order by price ascending where code = 'ABC'. I'm at a loss to figure out where to put the last two conditions in the following mysql statement. Please can someone advise. Many thanks
SELECT x.*
FROM (SELECT t.*,
CASE
WHEN #rating != t.rating THEN #rownum := 1
ELSE #rownum := #rownum + 1
END AS rank,
#rating := t.rating AS var_rating
FROM offers t
JOIN (SELECT #rownum := NULL, #rating := '') r
ORDER BY t.rating) x
WHERE x.rank <= 10
ALso, what if the rating column had entries like 1, 1, 1k, 1*, 1+, 2, 2, 2+, 3,3,3* etc, how would I be able to consider all of these entries as '1', 2 and 3 respectively in the same sql statement?
Try this:
SELECT x.*
FROM (SELECT t.*,
CASE
WHEN #rating != t.rating THEN #rownum := 1
ELSE #rownum := #rownum + 1
END AS rank,
#rating := t.rating AS var_rating
FROM offers t
JOIN (SELECT #rownum := NULL, #rating := '') r
WHERE code = 'ABC'
ORDER BY t.rating, price) x
WHERE x.rank <= 10
The changes are:
Added a WHERE clause after the JOIN clause
Added price to the ORDER BY clause.