I have two tables: songs and groups
i want limit the songs are match the group to 3
i tried this:
SELECT
groups.`IDgroup`,
groups.`name` AS g_name,
songs.`IDsong`,
songs.`name` AS s_name
FROM `groups`
LEFT OUTER JOIN songs ON (groups.`IDgroup` = songs.`IDgroup` LIMIT 3)
Put the limit out of parentheses:
SELECT
groups.`IDgroup`,
groups.`name` AS g_name,
songs.`IDsong`,
songs.`name` AS s_name
FROM `groups`
LEFT OUTER JOIN songs
ON groups.`IDgroup` = songs.`IDgroup`
LIMIT 3
It is generally not a good idea to put a limit on a query that does not explicitly order its results. The reason is that it could return different results over time.
So, you may want to consider adding an
ORDER BY groups.IDgroup, songs.IDsong
to your query (before the LIMIT 3), assuming that this combination is unique.
SELECT
g.`IDgroup`,
g.`name` AS g_name,
s.`IDsong`,
s.`name` AS s_name
FROM `groups` g
LEFT OUTER JOIN songs s
using ('idgroup')
LIMIT 3
This query will return the last 3 songs for each group:
SELECT
c.`IDgroup`,
c.`name` AS g_name,
s.`IDsong`,
s.`name` AS s_name
FROM
groups c
JOIN (
SELECT
IF(#C != c.IDgroup, #ROWNUM := 1, #ROWNUM := #ROWNUM +1) AS RN,
#C := c.IDgroup,
c.IDgroup,
s.IDsong,
s.name
FROM groups c
LEFT JOIN songs s ON c.`IDgroup` = s.`IDgroup`
CROSS JOIN (SELECT #C := '') t2
ORDER BY c.IDgroup ASC
) s ON c.`IDgroup` = s.`IDgroup`
JOIN JOIN (
SELECT IDgroup, MAX(rn) AS mx
FROM (
SELECT
IF(#C != c.IDgroup, #ROWNUM := 1, #ROWNUM := #ROWNUM +1) AS rn,
#C := c.IDgroup,
c.IDgroup
FROM groups c
LEFT JOIN songs s ON c.`IDgroup` = s.`IDgroup`
CROSS JOIN (SELECT #C := '') t2
ORDER BY c.IDgroup ASC
) t
GROUP BY IDgroup
) maxsong ON maxsong.IDgroup = c.IDgroup AND s.rn BETWEEN maxsong.mx-2 AND maxsong.mx
ORDER BY c.IDgroup ASC, s.`name` ASC
Fiddle: http://sqlfiddle.com/#!2/b65c3b/1
Take the LIMIT out of the parentheses:
SELECT
groups.`IDgroup`,
groups.`name` AS g_name,
songs.`IDsong`,
songs.`name` AS s_name
FROM `groups`
LEFT OUTER JOIN songs USING (`IDgroup`)
LIMIT 3
Related
I want to rank the total stats of a group of users and assign a rank variable to them.
I used this thread for the Rank variable.
This is my Query atm:
SELECT #rank := #rank + 1 AS rank
, SUM(stats.points) AS x
FROM
( SELECT #rank := 0 ) r
, groups
LEFT
JOIN user_group
ON groups.id = user_groups.clan
LEFT
JOIN stats
ON user_groups.user = stats.id
GROUP
BY groups.id
ORDER
BY x DESC
RANK | points
--------------
47 | 3400
1 | 2500
75 | 1200
As you can see the Sorting by Points works fine, but the Rank variable seems to just pick random values.
Can anyone find a way to assign the rank correctly?
Use a subquery for the aggregation and ordering:
SELECT id, sum_points, #rank := #rank + 1 AS rank
FROM (SELECT g.id, SUM(s.points) AS sum_points
FROM groups g LEFT JOIN
user_group ug
ON g.id = ug.clan LEFT JOIN
stats s
ON ug.user = s.id
GROUP BY g.id
ORDER BY sum_points DESC
) s CROSS JOIN
(SELECT #rank := 0) params;
This has been an issue in MySQL for a while -- variables don't work well with aggregation and ordering.
Note that in MySQL 8+, this is much more simply written as:
SELECT g.id, SUM(s.points) AS sum_points,
ROW_NUMBER() OVER (ORDER BY SUM(s.points) DESC) as rank
FROM groups g LEFT JOIN
user_group ug
ON g.id = ug.clan LEFT JOIN
stats s
ON ug.user = s.id
GROUP BY g.id
i'm trying to get ranking based on rating percentage so mysql query like
select c.id , sum((r.value * 20))/ count(r1.pagetypeid) as score, #curRank := #curRank + 1 AS rank from (SELECT #curRank := 0) cr, rating as r
inner join rateelement as r1 on r.elementid = r1.id
inner join ratesubscription as r2 on r.subscriptionid = r2.id
inner join consultant as c on r2.consultantid = c.id
where r1.displayorder not in (6) and r2.agencyid = 38
group by c.id order by score desc
but it returns wrong raking indexes
what's wrong with the query?
Ranking with variables often has issues with group by -- and even order by in the most recent versions of MySQL. So, use a subquery:
select x.*, (#curRank := #curRank + 1) AS rank
from (select c.id, sum((r.value * 20))/ count(r1.pagetypeid) as score
from rating r inner join
rateelement r1
on r.elementid = r1.id inner join
ratesubscription r2
on r.subscriptionid = r2.id inner join
consultant c
on r2.consultantid = c.id
where r1.displayorder not in (6) and r2.agencyid = 38
group by c.id
order by score desc
) x cross join
(SELECT #curRank := 0) cr;
how to convert this multiple UNION to simple query?
number of artist_id is dynamic.
45,122,95
or
100,20
or
89,9449
or
22,495,700,98
....
(SELECT b.`id`, b.`id`, b.`date`, b.`artist`, b.`title`, b.`photo`
FROM `tags_mp3s` a
INNER JOIN `mp3s` b ON b.`id` = a.`mp3_id` AND a.`artist_id` = 45
ORDER BY b.`date` DESC
LIMIT 5)
UNION ALL
(SELECT b.`id`, b.`id`, b.`date`, b.`artist`, b.`title`, b.`photo`
FROM `tags_mp3s` a
INNER JOIN `mp3s` b ON b.`id` = a.`mp3_id` AND a.`artist_id` = 122
ORDER BY b.`date` DESC
LIMIT 5)
UNION ALL
(SELECT b.`id`, b.`id`, b.`date`, b.`artist`, b.`title`, b.`photo`
FROM `tags_mp3s` a
INNER JOIN `mp3s` b ON b.`id` = a.`mp3_id` AND a.`artist_id` = 95
ORDER BY b.`date` DESC
LIMIT 5)
.....
thanks
In MySQL, you can use variables:
SELECT ta.*
FROM (SELECT m.*,
(#rn := if(#a = t.artist_id, #rn + 1,
if(#a := t.artist_id, 1, 1)
)
) as rn
FROM tags_mp3s t INNER JOIN
mp3s m
ON m.id = t.mp3_id CROSS JOIN
(SELECT #rn := 0, #a := -1) params
WHERE t.artist_id IN (. . . )
ORDER BY t.artist_id, m.date DESC
) ta
WHERE rn <= 5;
I need to assign a rank to TC5 not the id.
SELECT a.id, a.user_id, a.tc1, a.tc4, min(a.tc5), a.tc2, b.avatar, c.username, #curRank := #curRank + 1 AS Rank
FROM
treningove_casy a INNER JOIN
sn_users b ON a.user_id=b.id INNER JOIN
users c ON a.user_id=c.id , (SELECT #curRank := 0) r
WHERE a.tc2 LIKE 'Motokáry Modrice'
GROUP BY a.user_id
So how is the picture. Please help
The modified code
SELECT x.*, (#curRank := #curRank + 1) as Rank
FROM (SELECT a.id, a.user_id, a.tc1, a.tc4, min(a.tc5) as tc5,
a.tc2, b.avatar, c.username,
FROM sbhgl_chronoengine_chronoforms_datatable_treningove_casy a INNER JOIN
sbhgl_jsn_users b
ON a.user_id = b.id INNER JOIN
sbhgl_users c
ON a.user_id = c.id
WHERE a.tc2 LIKE 'Motokáry Modřice'
GROUP BY a.user_id
) x CROSS JOIN
(SELECT #curRank := 0) params
ORDER BY tc5 DESC;
SELECT a.id, a.user_id, a.tc1, a.tc4, a.tc2, b.avatar, c.username,
(select rank from (SELECT
IF (#score=s.tc5, #rank:=#rank, #rank:=#rank+1) rank,
#score:=s.tc5 tc5s
FROM treningove_casy s,
(SELECT #score:=0, #rank:=0) r
ORDER BY tc5 DESC) s ) as rank
FROM
treningove_casy a INNER JOIN
sn_users b ON a.user_id=b.id INNER JOIN
users c ON a.user_id=c.id , (SELECT #curRank := 0) r
WHERE a.tc2 LIKE 'Motokáry Modrice'
GROUP BY a.user_id
You can try above solution, Hope this will help you.
In MySQL, you typically use variables for ranks. In your case, you would use a subquery. I find that the variable method doesn't always work with GROUP BY:
SELECT x.*, (#curRank := #curRank + 1) as Rank
FROM (SELECT a.id, a.user_id, a.tc1, a.tc4, min(a.tc5) as tc5,
a.tc2, b.avatar, c.username,
FROM treningove_casy a INNER JOIN
sn_users b
ON a.user_id = b.id INNER JOIN
users c
ON a.user_id = c.id
WHERE a.tc2 LIKE 'Motokáry Modrice'
GROUP BY a.user_id
) x CROSS JOIN
(SELECT #curRank := 0) params
ORDER BY tc5 DESC;
Note: The use of table aliases is good. It is much easier to understand a query, though, if the aliases are abbreviations for the table names.
I'm using this query:
SELECT A.place_idx,A.place_id,B.TOTAL_CNT,(#r := #r + 1) AS rank FROM CUSTOM_LIST
AS A
INNER JOIN
(SELECT #r := 0)
AS C
INNER JOIN
(SELECT place_id,COUNT(place_id) AS TOTAL_CNT from COUNT_TABLE GROUP BY place_id)
AS B ON B.place_id=A.place_id order by B.TOTAL_CNT desc;
Which gives this result:
But I want this result:
How do I need to modify my query? What am I doing wrong?
SELECT *,(#r := #r + 1) AS rank FROM
(
SELECT A.place_idx,A.place_id,B.TOTAL_CNT FROM CUSTOM_LIST
AS A
INNER JOIN
(SELECT place_id,COUNT(place_id) AS TOTAL_CNT from COUNT_TABLE GROUP BY place_id)
AS B ON B.place_id=A.place_id order by B.TOTAL_CNT desc
) AS T, (SELECT #r := 0) AS tt
Your C.rank is getting calculated as they are processed, not after they are sorted. There is really no need for this data, anyways. Since you're sorting the rows by your metric, you know the first row is the first rank, etc. You can handle it on the programming side of things after you pull it out.
Alternatively, you can put what you have in an inner select, then do the rank after.