I'm implementing a leaderboard for our group project.
this is my query for counting the number of status userid 2 have in the table.
$query = "SELECT COUNT(content) FROM status WHERE userid=2 ";
now, how could i query the userid with most number of status?
example table
|| content || userid ||
|| x || 1 ||
|| xx || 1 ||
|| y || 2 ||
|| yy || 2 ||
|| yyy || 2 ||
|| z || 3 ||
with result
1st = 2 with 3 status
2nd = 1 with 2 status
3rd = 3 with 1 status
what will i do to limit the result? what if i only need the top 5?
in relation to this problem
i was thinking of adding another column(number_of_status) in the user table instead of this multiple queries... which is better?
THANK YOU!
Should be able to do this with a GROUP BY:
SELECT userid, COUNT(*) AS status_count
FROM status
GROUP BY userid
ORDER BY status_count DESC
LIMIT 5
You can achieve this with a GROUP BY query, and LIMIT.
SELECT userid, COUNT(content) as statuses
FROM status
GROUP BY userid
ORDER BY statuses DESC
LIMIT 5
Related
I have 3 tables in mySQL called tb_tour_trip, tb_facilities and tb_master_facilities which have many to many relationship. I want to select 1 data in tb_tour_trip which have 2 or more master_facilities. example : i wanna select trip which have facilities: AC and WiFi
This is the tb_tour_trip table :
tb_tour_trip
============
id || name || description || price
===================================
1 || trip1 || example trip || $200
2 || trip2 || example trip || $300
This is the tb_facilities table (For MANY to MANY relations):
tb_facilities
============
id || id_master_facilities_ref || id_tour_trip_ref
===================================
1 || 1 || 1
2 || 2 || 1
3 || 1 || 2
3 || 3 || 2
And this is my tb_master_facilities table:
tb_master_facilities
============
id || name || status
====================
1 || WiFi || 1
2 || AC || 1
3 || TV || 1
if tried this Query :
SELECT id_tour_trip_ref FROM tb_facilities WHERE id_master_facilities_ref IN(1,2);
this show me id_tour_trip which have facilities : AC or Wifi, but that's not what i want.
I want the id_tour_trip which have AC AND Wifi only.
Exactly output is just :
id_tour_trip_ref
================
1
How can i do that? thanks before.
There's a number of ways to do this, but a reasonably easy to read/maintain method is this:
SELECT id
FROM tb_tour_trip AS ttt
WHERE (
SELECT COUNT(DISTINCT id_master_facilities_ref)
FROM tb_facilities AS tbf
WHERE tbf.id_tour_trip_ref = ttt.id
AND tbf.id_master_facilities_ref IN (1, 2)
) = 2;
If only to get your exact output, this could also work:
SELECT id_tour_trip_ref
FROM tb_facilities INNER JOIN tb_master_facilities ON tb_facilities.id=tb_master_facilities.id
WHERE name IN ("WiFi","AC") AND id_master_facilities_ref IN (1,2)
GROUP BY id_tour_trip_ref;
One method is aggregation with a HAVING clause:
SELECT f.id_tour_trip_ref
FROM tb_facilities f INNER JOIN
tb_master_facilities
ON f.id = mf.id
WHERE f.name IN ('WiFi', 'AC')
GROUP BY f.id_tour_trip_ref
HAVING COUNT(*) = 2;
I would join all of the tables together and just do 'where condition1 and condition2. This is propably less efficient but imho more comprehensive.
select distinct tb_tour_trip.id from tb_tour_trip
inner join tb_facilities on tb_facilities.id_tour_trip_ref = tb_tour_trip.id
inner join tb_master_facilities on tb_master_facilities.id = tb_facilities.id_master_facilities_ref
where tb_master_facilities.name = 'WiFi'
and tb_master_facilities.name = 'AC'
i've found the answer from forum on Facebook. thanks for all your advice :)
This is the exactly i need.
SELECT id_tour_trip_ref, GROUP_CONCAT(id_master_facilities_ref) AS facilities FROM tb_facilities GROUP BY id_tour_trip_ref HAVING FIND_IN_SET('1', facilities) > 0 AND FIND_IN_SET('2', facilities) > 0
I have a result of MySQL after Joining two tables as follows:-
ID || Category || Cost ||
========================||==================||==================||
AMWP/ABC/2016-17/1 || 1 || 123.88 ||
AMWP/CDF/2016-17/2 || 2 || 222.99 ||
AMWP/GHI/2016-17/3 || 3 || 133.90 ||
AMWP/ABC/2017-18/1 || 1 || 100.10 ||
AMWP/CDF/2017-18/2 || 2 || 200.20 ||
AMWP/GHI/2017-18/3 || 3 || 100.00 ||
I want to extract summary as per Catergory and Count of each Catergory and Sum of Cost for Only with Condition where ID has Like one of ABC/CDF/GHI and Financial Year Like 2016-17/2017-18
select category, sum(Cost)
from your_tables
where
( ID like ‘%/ABC/% or ID like ‘%/CDF%/’ or ID like ‘%/GHI/%’ )
and
( ID like ‘%/2016-17/%’ or ID like ‘%/2017-18/%’ )
and <joining condition>
group by category;
I got it the way I desired. In the following SQL, I am Using Sum instead of Count to Add 1 to TotWks whenever the Condition is True. Also, I just Adding the Cost Field to TotCost whenever the Condition is True.
SELECT
Category,
SUM(if(ID LIKE '%2017-18%' AND ID like ‘%/ABC/%, 1, 0)) AS `TotWks`,
SUM(if(ID LIKE '%2017-18%' AND ID like ‘%/ABC/%, `amwplist`.`Cost`, 0)) AS `TotCost`
FROM <main_Table>
LEFT OUTER JOIN <join_Table> ON <main_Table.ID> = <join_Table. ID>
GROUP BY <main_Table.ID>
If I Omit the GROUP BY Clause, then I will grand Total under TotWks and TotCost.
Thanks for all the help.
I have a Table:
tblUserLoginRecord
ID || User || LoginTime
1 || Peter|| 2017-07-03
2 || Susan|| 2017-07-04
3 || Sam || 2017-07-05
4 || Sam || 2017-07-07
5 || Sam || 2017-07-08
6 || Susan|| 2017-07-09
I want to have a result that show the last LoginTime Group By User(Using ID DESC will be fine too):
ID || User || LoginTime
1 || Peter|| 2017-07-03
5 || Sam || 2017-07-08
6 || Susan|| 2017-07-09
How I do it now is:
SELECT * FROM (SELECT * FROM tblUserLoginRecord ORDER BY ID DESC) a GROUP BY User;
But it will be much slower if the table growth bigger. How can I make it better?
Thank you.
You can use select only once if you are using mysql. That will speed up things up.Also your query should be better. See below and use it, you will see the difference
Select ID , User, max(LoginTime) as date
from tblUserLoginRecord
group by User
You need to build better queries for better results which will help beyond your expectations.
Table is like this:
id || name || team || goals || data
1 || Kitten || Pets || 3 || 12
2 || Dog || Pets || 2 || 11
3 || Kitten || Animals || 5 || 6
4 || Kitten || Cats || 4 || 3
5 || Dog || Pets || 2 || 9
My basic query is:
SELECT name, team, SUM(goals), SUM(data) FROM table GROUP BY name
Results are like:
name || team || sum(goals) || sum(data)
Kitten || Pets || 12 || 21
Dog || Pets || 4 || 20
I want to be able to get the most recent team (the highest id), but so far all I've been able to get is the first team listed with the query as written. I can get the first or last team alphabetically by using min(team) or max(team), but that doesn't always give the last record that I need. Help? Also, sorry I don't know how to format things well here.
There are different ways of doing this, but here is one.
You can get the most recent record for each team like this:
select * from table where id in(select max(id) from table group by team)
I think this may be what you're asking for:
SELECT name, team, SUM(goals), SUM(data)
FROM table t1
JOIN (SELECT team
FROM table
ORDER BY id DESC
LIMIT 1) t2
ON t1.team = t2.team
GROUP BY name
So I have two tables. One with amount of shares that people have:
Person_ID || Shares
1 || 100
2 || 150
3 || 315
4 || 75
5 || 45
...
and another with info whether a person is present (there are two columns specifying that) and what group does he belongs to:
Person_id || barcode_presence || manual_presence || group_id
1 || NULL || 1 || NULL
2 || 1 || NULL || 1
3 || 1 || 0 || 2
4 || 0 || NULL || 1
5 || 1 || 0 || 1
...
I need to find out the sum of all present and sum of all absent shares in every single group (NULL group is also a group).
The thing I cannot figure out is that whether the person is present or absent is figured out by the combination of two columns (barcode_presence and manual_presence):
if manual_presence = 1 --> present
else if (manual_presence = NULL and barcode_presence = 1) --> present
everything else is absent.
Thats what i've got so far.
SELECT presence_list.Person_id, presence_list.person_name,
presence_list.barcode_presence, presence_list.manual_presence,
presence_list.group_id, people_data.Share
, sum(people_data.Share)
FROM presence_list
INNER JOIN people_data
ON presence_list.Person_id = people_data.Person_ID
WHERE meeting_id = 1 AND voting_id = 0
GROUP BY presence_list.group_id,
barcode_presence,
manual_presence
ORDER BY presence_list.group_id
;
But obviously that does not give me the desired result. it groups by every possible combination of group_id, barcode_presence and manual_presence like following:
Person_id || barcode_presence || manual_presence || group_id || share || sum(shares)
1 || NULL || 1 || NULL || 100 || 100
2 || 1 || NULL || 1 || 150 || 150
4 || 0 || NULL || 1 || 75 || 75
5 || 1 || 0 || 1 || 45 || 45
3 || 1 || 0 || 2 || 315 || 315
So i'm looking for a way to (in this case) connect person with id 4 and 5, because they are both absent and they are from the same group, like this:
Person_id || barcode_presence || manual_presence || group_id || share || sum(shares)
1 || NULL || 1 || NULL || 100 || 100
2 || 1 || NULL || 1 || 150 || 150
5 || 1 || 0 || 1 || 45 || **120**
3 || 1 || 0 || 2 || 315 || 315
I've tried using HAVING clause but I didn't found a way for it to handle complex expressions like manual_presence = 1 OR (manual_presence is null AND barcode_presence = 1)
Any ideas or suggestions would be appreciated! thanks beforehand!
if only one of the two columns can ever be populated, Use coalesce...
Group By group_id, Coalesce(barcode_presence, manual_presence)
if not, (can, say, the barcode_presence = 1 and the presence = 0?), then yu need to decide what groups of possible combinations of values you want to group by, and just group by an expression that does that... drawing a chart of value combinations may help...
barcode value
manual Null 0 1
Null GrpA GrpA GrpB
0 GrpC GrpC GrpB
1 GrpB GrpB GrpB
say you want to group by those where both are 0, and all the others, then you would write...
Group By group_id, case When isnull(barcode_presence, 0) = 0
And isnull(manual_presence, 0) = 0 Then 0 Else 1 End
You can use a case to make a group for present and non-present people:
select group_id
, case
when barcode_presence = 1 and manual_presence = 1 then 1
else 0
end
, sum(share)
from presence_list pl
join people_data pd
on pl.person_id = pd.person_id
group by
group_id
, case
when barcode_presence = 1 and manual_presence = 1 then 1
else 0
end
order by
group_id
If I understand correctly, I think producing two columns is the way to go:
select pd.group_id,
SUM(isPresent * pd.shares) as PresentShares,
SUM((1 - isPresent)*pd.shares) as NotPresentShares
from (select pl.*,
(case when manual_presence = 1 or
manual_precence is null and barcode_presence = 1
then 1 else 0
end) as IsPresent
end
from presence_list pl
) pl join
people_data pd
on pl.Person_id = pd.Person_ID
group by pd.group_id
The subquery just applies your logic to create a flag that is 1 for present and 0 for not-present. Conveniently, when coded this way, "1 - IsPresent" is 1 for not-present and 0 for present.
This value then used in the aggregation to aggregate the shares. You could have the outer query be:
select group_id, IsPresent, sum(pd.shares)
from . . .
group by group_id, IsPresent
If you really wanted the values on separate rows.