Increment counter in mysql and GROUP_CONCAT - mysql

Here is my mysql query:
SELECT users.id, user.name, category.id,
GROUP_CONCAT(category.name) AS catName,
#rownum := #rownum + 1 AS row_number
FROM users
JOIN usecat ON id_users=users.id
JOIN category ON id_category=category.id
CROSS JOIN (select #rownum := 0) r
GROUP BY users.id
Result: AAA-1, BBB-3, CCC-8,...
I'd like to get this result: AAA-1, BBB-2, CCC-3,...
Can you help me change this query? Thanks.

Try this:
SET #rownum=1;
SELECT *, #rownum := #rownum + 1 AS row_number
FROM (SELECT users.id, user.name, category.id,
GROUP_CONCAT(category.name) AS catName
FROM users
JOIN usecat ON id_users=users.id
JOIN category ON id_category=category.id
GROUP BY users.id) t;

Related

MySQL row number with ORDER BY

Right now I have this:
SELECT
#rownum := #rownum + 1 AS rownum,
T1.*
FROM
(
SELECT user.username, points
FROM scores
JOIN users AS user ON user.id = scores.user_id
) AS T1, (SELECT #rownum := 0) AS r
ORDER BY T1.points DESC, rownum ASC
And this returns usernames, points and row number. Points are ordered but row numbers are all messed up. If I put ORDER BY into the nested select then row nubmers are ordered but points are not. So what I need to change so that I get points ordered in descending order and row number would be in ascending, what I wanna create is leaderboards, so that user whit most point is first etc.
It looks like you need your rownum to be paired up with points that have been pre-ordered. Hence you need to move ORDER BY on points into the nested select:
SELECT
#rownum := #rownum + 1 AS rownum,
T1.*
FROM
(
SELECT user.username, points
FROM scores
JOIN users AS user ON user.id = scores.user_id
ORDER BY points DESC
) AS T1, (SELECT #rownum := 0) AS r
ORDER BY rownum ASC
Does this do what you want?
SELECT (#rownum := #rownum + 1) AS rownum,
us.*
FROM (SELECT u.username, s.points
FROM scores s JOIN
users u
ON u.id = s.user_id
ORDER BY s.points DESC
) us CROSS JOIN
(SELECT #rownum := 0) params;
Basically, this just leaves the ordering in the subquery.
If points is not a number, then use ORDER BY (s.points + 0) DESC in the subquery. Or fix the data so it is stored as a number.

Rank function in MySQL assign a rank

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.

Mysql how limit left join results

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

MySQL - Rank COUNT from GROUP BY returning nil

I'm trying to follow this example: MySQL - ranking by count() and GROUP BY but my rank column keeps returning nil.
Here's my query:
SELECT
#rownum := #rownum+1 AS rank,
q.id,
q.Name,
q.count
FROM
(SELECT
Accounts.id,
Accounts.Name,
COUNT(Accounts.Name) AS count
FROM
player_to_team_histories
INNER JOIN
team_histories ON team_histories.id = player_to_team_histories.team_history_id
INNER JOIN
teams ON teams.id = team_histories.team_id
INNER JOIN
accounts ON accounts.id = teams.account_id
WHERE
accounts.AccountTypeId = 1 AND player_id IN (SELECT
player_id
FROM
player_to_team_histories
WHERE
player_to_team_histories.not_valid IS NULL AND team_history_id = (SELECT
team_history_id
FROM
player_to_team_histories
INNER JOIN
team_histories ON team_histories.id = player_to_team_histories.team_history_id
WHERE
player_to_team_histories.id = 574651))
GROUP BY Accounts.Name
ORDER BY count DESC)q
Every column except rank is returning as expected, and rank is returning null for every row.
You have to initialize your rownum to 0 before starting to increment it, either by
SET #rownum := 0;
before the query, or by a separate SELECT clause after your first FROM:
SELECT ...
FROM
(SELECT #rownum := 0 ) counter,
(SELECT
... )

Mysql SELECT query used to find postion

In the above table, c position is 3.
Is there any function to find the position in Mysql?
update
try
select #rownum:=#rownum+1 ‘theposition’, t.* from mytable t, (SELECT #rownum:=0) r order by t.USER desc;
Use this:
SELECT x.user,
x.position,
x.number
FROM (SELECT t.user,
t.number,
#rownum := #rownum + 1 AS position
FROM TABLE t
JOIN (SELECT #rownum := 0) r
ORDER BY t.number DESC) x
WHERE x.user = 'c'
You can then get his position from x.position
I recommend you to add an id field. i don't know of any function to do that. you can select * and then in a script language search it or use a subquery. but i don't recommend that.
SELECT
#rowNumber := #rowNumber + 1 'RowNumber',
u.*
FROM Users u,
(SELECT #rowNumber := 0) r
ORDER BY u.User ASC