:-)
I have this script, which find a users position taken from the number of credits.
It all works, but i have a little problem. If two users have the same credits, both of them will be on the same position.
Can I do, so if there are more users with same credits, then the system need to order by the users ID and out from that give them a position?
This is my code so far:
$sql = "SELECT COUNT(*) + 1 AS `number`
FROM `users`
WHERE `penge` >
(SELECT `penge` FROM `users`
WHERE `facebook_id` = ".$facebook_uid.")";
$query_rang = $this->db->query($sql);
So if i have this:
ID -------- Credits
1 -------- 100
2 -------- 100
3 -------- 120
Then the rank list should be like this:
Number 1 is user with ID 3
Number 2 is user with ID 1
Number 3 is user with ID 2
ORDER BY credits DESC, id ASC. This will sort by credits and break ties with the id.
UPDATE
I understand now that you want the ranking information for the user, not just to sort the users by credits and ids. This will give you the complete list of users and their rankings:
SELECT #rank:=#rank+1 AS rank, users.id, users.facebook_id FROM users, (SELECT #rank:=0) dummy ORDER BY penge DESC, id ASC
Getting the row number is the tricky bit solved by this blog post:
http://jimmod.com/blog/2008/09/displaying-row-number-rownum-in-mysql/
$sql = "SELECT COUNT(*) + 1 AS `number` FROM `users` WHERE `penge` > (SELECT `penge` FROM `users` WHERE `facebook_id` = ".$facebook_uid.") ORDER BY COUNT(*) + 1 desc, users.ID";
$query_rang = $this->db->query($sql);
Later EDIT:
I don't understand why you still have the same results....
I made a quick test. I have created a table:
Test: ID (Integer) and No (Integer)
I have inserted some values:
id no
1 1
1 1
1 1
2 1
3 1
4 1
4 1
5 1
Now, if I run:
SELECT
id, COUNT(*) + 1 AS `number`
FROM
test
GROUP BY
id
I get:
id number
1 4
2 2
3 2
4 3
5 2
But if I add ORDER BY:
SELECT
id, COUNT(*) + 1 AS `number`
FROM
test
GROUP BY
id
ORDER BY
count(*) desc, id
then I get:
id number
1 4
4 3
2 2
3 2
5 2
Related
I have a table which stores user items, the two key columns which I would like to use in this query are user_id and item_id. The id field in the example is not needed but just added to show these aren't the only two columns in the table.
----------------------
id user_id item_id
----------------------
1 1 324
2 1 324
3 3 324
4 2 230
5 4 324
The query which I would like to construct should return the top 10 users who have the most items with a specific item id.
So for example if I wanted to run the query against the item ID 324 I should get the following result.
-------------------
user_id item_count
-------------------
1 2
3 1
4 1
2 0
try this
select user_id , count(*) as item_count from table
where item_id = 324 group by user_id order by item_count desc limit 10
limit 10 will show you the top 10 users and order by desc sort from high to low.
However, the above query will not give you the 0 count as per your question. If you really want the zero count you can try this: (assuming your table name is userlist)
SELECT distinct user_id,
(select
count(*) from `userlist`
where user_id=u.user_id and item_id=324
) as item_count FROM `userlist` u
order by item_count desc
I couldn't create the database in my local, but I think this will do the trick
SELECT user_id, COUNT(item_id) as item_count
FROM TABLE_NAME
WHERE item_id = 324
GROUP BY item_id
ORDER BY item_count;
I'm going to select the highest result in my "quiz" table there is 5 type of data:
quizid, userid, quizdate, result, topicid
1 JAKE 1/7/2015 60 1
2 JAKE 1/7/2015 80 1
3 JAKE 1/7/2015 100 2
i wanna show each topic and user highest score only once.
But it only show the first highest score from the user, after user redo the quiz again it wont show the highest score.
Example: Userid JAKE has done first time quiz have 60 mark at quiz 1, when he redo quiz 1 and get 80 marks it still show 60mark at the Table.
Select userid,topicid, MAX(result) as result
FROM quiz GROUP BY userid, topicid
ORDER BY result desc
The final result should be show 80 for JAKE at topic 1, but my result was
1 JAKE 1/7/2015 60 1
3 JAKE 1/7/2015 100 2
Hey you should used it like. if you want complete record with max result
select * from (Select userid,topicid, result as result
FROM quiz ORDER BY result desc) as t GROUP BY t.userid, t.topicid
Try following,
Select userid, topicid, result from
(
Select
row_number() over (order by userid, topicid, result desc) row_id,
userid,
topicid,
result
FROM quiz
) t
where row_id = 1
Music table
id | title
1 Rap God
2 Blank Space
3 Bad Blood
4 Speedom
5 Hit 'em up
Like table
u_id | m_id
1 1
1 2
1 4
1 5
2 3
2 4
2 5
3 1
3 5
4 1
4 2
4 5
Now if someone visits music with m_id = 1
Then the output might be like
m_id
5
2
4
To explain this a bit...
As m_id = 1 is liked by users -> {1,3,4} which in turn likes ->{2,4,5} musics. Since m_id=5 is liked by max number of users its first followed by m_id = 2 and m_id = 4.
My Try
I queried the users who liked m_id = 1
SELECT u_id FROM likes WHERE m_id =1
Then i stored in in an array and selected each of their likes and
arranged them in desc order of count.
But it is a very slow and long process is there any way i can do this ?
p.s I have heard of Association Rules and Bayesian theorem can be user to achieve this. But can anyone help me out with an example ?
You can JOIN back on the Like table and do something like this.
SELECT also_like.m_id, COUNT(also_like.m_id)
FROM [like] AS did_like
JOIN [like] AS also_like ON
also_like.u_id = did_like.u_id
AND also_like.m_id != did_like.m_id
WHERE did_like.m_id = 1
GROUP BY also_like.m_id
ORDER BY COUNT(also_like.m_id)
Essentially you are getting a list of users who liked an item then getting a complete list of those user's likes excluding the item they just liked.
You can then add a HAVING clause or LIMIT to filter things down a bit more.
using a subquery ...
SELECT m_id, count(u_id) as Rank FROM `like`
WHERE u_id in
(
SELECT u_id
FROM `like`
WHERE m_id = 1
)
AND m_id <> 1
GROUP BY m_id
ORDER BY Rank DESC
and optionally
LIMIT 0, 10
or how many "alsolikes" you want to display
My issue is that I need to paginate data from this query:
function search($search_term, $limit, $offset)
{
$id = $this->auth->get_user_id();
$query = $this->db->query("
SELECT user_id,
first_name,
cars_name,
cars_id
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE '$id'
AND activated = 1
AND banned = 0
AND first_name LIKE '%$search_term%'
ORDER BY first_name ASC
");
$search_data = array();
foreach ($query->result() as $row) {
$search_data[$row->user_id]['name'] = $row->first_name;
$search_data[$row->user_id]['cars'][$row->cars_id] = array(
'cars_name' => $row->cars_name);
}
return $search_data;
}
A sample data table / query response would be:
1 JOE HONDA 123
1 JOE TOYOTA 124
2 MAC VW 125
2 MAC HONDA 126
2 MAC TESLA 127
3 STU SUBARU 128
3 STU KIA 129
-----------
Page 1
-----------
1 JOE HONDA 123
TOYOTA 124
2 MAC VW 125
HONDA 126
------------
Page 2
------------
3 STU SUBARU 128
KIA 129
If I enter a limit and offset at the end of MySQL query
...
LIMIT $limit
OFFSET $offset;
");
the limit and offset are applied to the total number of rows, not the the number of rows grouped by user.
I've tried using GROUP BY but was unable to make it work.
My goal is to make the query as above but LIMIT and OFFSET the query by a number of rows that counts users, not all rows.
Any ideas?
I don't see a way to do this in one query. My solution would be to get the count of unique ID's using a group by query with the same parameters:
SELECT COUNT(1) AS uid_count
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
GROUP BY user_profiles.user_id
WHERE user_id NOT LIKE '$id'
AND activated = 1
AND banned = 0
AND first_name LIKE '%$search_term%'
Then fetch the uid_countmysql_num_rows and use that to calculate pagination variables for the above query.
The solution really is to use a GROUP BY clause:
SELECT SQL_CALC_FOUND_ROWS
user_id,
first_name,
cars_name,
cars_id
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE '$id'
AND activated = 1
AND banned = 0
AND first_name LIKE '%$search_term%'
GROUP BY user_id
ORDER BY first_name ASC
LIMIT 100
The order is important. GROUP BY first, then ORDER BY, and then OFFSET/LIMIT.
Notice the SQL_CALC_FOUND_ROWS up there? After the query has executed, if you want to get the total row count (including those who aren't returned because of the LIMIT clause), just use:
SELECT FOUND_ROWS() AS `count`
And fetch the count column.
However, like you said, the rows will collapse and you will lose some cars_name and cars_id values.
Another solution is to use GROUP_CONCAT, then split it in PHP:
SELECT
user_id,
first_name,
GROUP_CONCAT(cars_name SEPARATOR ','),
GROUP_CONCAT(cars_id SEPARATOR ','),
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE '$id'
AND activated = 1
AND banned = 0
AND first_name LIKE '%$search_term%'
ORDER BY first_name ASC
LIMIT 100
This would give you something like:
1 JOE HONDA,TOYOTA 123,124
2 MAC VW,HONDA,TESLA 125,126,127
3 STU SUBARU,KIA 128,129
If you want to get a list like this
Page 1
----------------------
1 JOE HONDA 123
1 JOE TOYOTA 124
Page 2
----------------------
2 MAC VW 125
2 MAC HONDA 126
2 MAC TESLA 127
Page 3
----------------------
3 STU SUBARU 128
3 STU KIA 129
Forget about limit, do this instead:
A - First retrieve a list of user id's and insert that into a temp table
CREATE TEMPORARY TABLE `test`.`temp_user_ids` (
`id` INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
`user_id` INTEGER UNSIGNED NOT NULL,
PRIMARY KEY (`id`)
)
ENGINE = MEMORY
B - Next insert the relavant user_id's into the table.
INSERT INTO temp_user_ids
SELECT null, user_id
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE '$id'
AND activated = 1
AND banned = 0
AND first_name LIKE '%$search_term%'
ORDER BY user_id DESC /*insert in reverse order !*/
The lowest user_id is the last_insert_id in the temptable, and the temp_table
items are in sequential order.
C - Set the SQL #var #current_id to the last_insert_id in the temp_table.
SELECT #current_id:= LAST_INSERT_ID()
D - Next select relevant rows from the table, using only the user_id you want.
SELECT count(*) as row_count,
up.user_id,
first_name,
group_concat(cars_name) as car_names,
group_concat(cars_id) as car_ids,
FROM user_profiles up
LEFT JOIN cars
ON cars.id_fk = up.user_id
INNER JOIN temp_user_ids t
ON (t.user_id = up.user_id)
WHERE t.id = #current_id
GROUP BY up.user_id
ORDER BY cars.id
E - Now lower the #current_id
SELECT #current_id:= #current_id - 1;
F - And repeat step D and E until there's no more rows to be had.
The first field row_count tells you the number of rows aggregated in the fields
car_names and car_ids. You can separate these fields by using php's explode.
If I have a single field, say, project_id where I want to count the occurrences, I would do something like:
select project_id, count(project_id) as count from tbl group by project_id, order by count desc
What if I want to count the occurrences of a combination of two fields in the same table, i.e. count the number of rows where the combination of project_id and service_id are unique?
So, so I have records in my table like:
project_id service_id
1 1
1 2
1 2
1 2
1 2
1 3
1 4
1 4
1 4
I would want the result of my query to be something like:
project_id service_id count
1 1 1
1 2 4
1 3 1
1 4 3
select project_id, service_id, count(*) as count
from tbl group by project_id, service_id
order by count(*) desc
Just add service_id to your group by and select list. That should do it.
EDIT -
As per comment from #Rajah it seems that for your expected output, you need to use
order by project_id asc, service_id asc