I need a help constructung an sql query for mysql database. 2 Table as follows:
tblcities (id,name)
tblmembers(id,name,city_id)
Now I want to retrieve the 'city' details that has maximum number of 'members'.
Regards
SELECT tblcities.id, tblcities.name, COUNT(tblmembers.id) AS member_count
FROM tblcities
LEFT JOIN tblmembers ON tblcities.id = tblmembers.city_id
GROUP BY tblcities.id
ORDER BY member_count DESC
LIMIT 1
Basically: retrieve all cities and count how many members each has, sort by that member count in descending order, making the highest count first - then show only that first city.
Terrible, but that's a way of doing it:
SELECT * FROM tblcities WHERE id IN (
SELECT city_id
FROM tblMembers
GROUP BY city_id
HAVING COUNT(*) = (
SELECT MAX(TOTAL)
FROM (
SELECT COUNT(*) AS TOTAL
FROM tblMembers
GROUP BY city_id
) AS AUX
)
)
That way, if there is a tie, still you'll get all cities with the maximum number of members...
Select ...
From tblCities As C
Join (
Select city_id, Count(*) As MemberCount
From tblMembers
Order By Count(*) Desc
Limit 1
) As MostMembers
On MostMembers.city_id = C.id
select top 1 c.id, c.name, count(*)
from tblcities c, tblmembers m
where c.id = m.city_id
group by c.id, c.name
order by count(*) desc
Related
I have 2 tables: 1st is comment, 2nd is rating
SELECT * FROM comment_table a
INNER JOIN (SELECT comment_id, SUM(rating_value) AS total_rating FROM rating_table GROUP BY comment_id) b
ON a.comment_id = b.comment_id
ORDER BY b.total_rating DESC
I tried the above SQL but doesn't work!
Object is to display a list of comments order by rating points of each comments.
SELECT s.* FROM (
SELECT * FROM comment_table a
INNER JOIN (SELECT comment_id, SUM(rating_value) AS total_rating FROM rating_table GROUP BY comment_id) b
ON a.comment_id = b.comment_id
) AS s
ORDER BY s.total_rating DESC
Nest it inside an another select. It will then output the data in the correct order.
Problem in general words: I need to select value from one table referenced to the most repeated values in another table.
Tables have this structure:
screenshot
screenshot2
The question is to find country which has the most results from sportsmen related to it.
First, INNER JOIN tables to have relation between result and country
SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id);
Then, I count how much time each country appear
SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id))
GROUP BY country
;
And got this screenshot3
Now it feels like I'm one step away from solution ))
I guess it's possible with one more SELECT FROM (SELECT ...) and MAX() but I can't wrap it up?
ps:
I did it with doubling the query like this but I feel like it's so inefficient if there are millions of rows.
SELECT country
FROM (SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id)
) GROUP BY country
)
WHERE highest_participation = (SELECT MAX(highest_participation)
FROM (SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id)
) GROUP BY country
))
Also I did it with a view
CREATE VIEW temp AS
SELECT country as country_with_most_participations, COUNT(country) as country_participate_in_#_comp
FROM(
SELECT country, competition_id FROM result
INNER JOIN sportsman USING(sportsman_id)
)
GROUP BY country;
SELECT country_with_most_participations FROM temp
WHERE country_participate_in_#_comp = (SELECT MAX(country_participate_in_#_comp) FROM temp);
But not sure if it's easiest way.
If I understand this correctly you want to rank the countries per competition count and show the highest ranking country (or countries) with their count. I suggest you use RANK for the ranking.
select country, competition_count
from
(
select
s.country,
count(*) as competition_count,
rank() over (order by count(*) desc) as rn
from sportsman s
inner join result r using (sportsman_id)
group by s.country
) ranked_by_count
where rn = 1
order by country;
If the order of the result rows doesn't matter, you can shorten this to:
select s.country, count(*) as competition_count
from sportsman s
inner join result r using (sportsman_id)
group by s.country
order by count(*) desc
fetch first rows with ties;
You seem to be overcomplicating this. Starting from your existing join query, you can aggregate, order the results and keep the top row(s) only.
select s.country, count(*) cnt
from sportsman s
inner join result r using (sportsman_id)
group by s.country
order by cnt desc
fetch first 1 row with ties
Note that this allows top ties, if any.
SELECT country
FROM (SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id)
) GROUP BY country
order by 2 desc
)
where rownum=1
In oracle, i have two tables - Supplier and customer. Each has a field name 'Country'
I have to find the total number of suppliers and customers by Country and then add these two counts to display as a single count for each country.
I have two queries, one for each table(supplier and customer). But how to combine them?
SELECT S.Country, count(distinct(S.CompanyName)) as cnt
from NW_Suppliers S
group by S.Country
SELECT C.Country, count(distinct(C.CustomerID)) as cnt1
from NW_Customers C
group by C.Country
Can anyone please help?
Just join the two together:
SELECT COALESCE( S.Country, C.Country ) AS country,
COALESCE( c.cnt, 0 ) + COALESCE( s.cnt, 0 ) AS total
FROM ( SELECT Country,
COUNT( DISTINCT CompanyName ) AS cnt
FROM NW_Suppliers
GROUP BY Country
) S
FULL OUTER JOIN
( SELECT Country,
COUNT( DISTINCT CustomerID ) AS cnt
FROM NW_Customers
GROUP BY Country
) C
ON ( s.country = c.country )
Or UNION the two tables:
SELECT Country,
COUNT( DISTINCT name ) AS total
FROM (
SELECT Country, CompanyName AS Name
FROM NW_Suppliers
UNION
SELECT Country, CustomerID
FROM NW_Customers
)
GROUP BY Country
They will give slightly different answers depending on how you want to treat duplicates between the two tables but its unclear from your description what your intended behaviour should be.
SELECT S.Country, count(distinct(S.CompanyName)) as cnt
from NW_Suppliers S
group by S.Country
Union all
SELECT C.Country, count(distinct(C.CustomerID)) as cnt
from NW_Customers C
group by C.Country
I have a table that is having 2 duplicate rows (total of 3 rows), so I used the code below to get the duplicate value in the column
SELECT CustNo, COUNT(*) TotalCount
FROM Rental
GROUP BY CustNo
HAVING COUNT(*) > 1
ORDER BY COUNT(*) DESC
So once I get the repeated value, I need to get the CustNo derived as duplicate from the customer table. How do I go about taking this value and using it in the select statment all in the same query.
I also have the select statement prepared like this.
Select * from Customer where CustNo = 'T0002';
Thanks.
Select * from Customer
where CustNo IN
(
SELECT CustNo
FROM Rental
GROUP BY CustNo
HAVING COUNT(*) > 1
)
You can use join:
SELECT c.*
FROM (SELECT CustNo, COUNT(*) TotalCount
FROM Rental
GROUP BY CustNo
HAVING COUNT(*) > 1
) cc JOIN
Customer c
on cc.CustNo = c.CustNo;
Select C.* from Customer C RIGHT JOIN (
SELECT CustNo
FROM Rental
GROUP BY CustNo
HAVING COUNT(*) > 1) D
ON C.CustNo = D.CustNo
You can also try this,
With tblDups as(
select CustNo,count(CustNo) as TotalCount from a_rental
Group by CustNo
Having count(CustNo) >1)
select b.* from a_rental b
inner join tblDups a on a.CustNo = b.Custno
I have 3 tables, but I can only get to join another table count. See below.
The one below works like a charm, but I need to add another "count" from another table.
there is a 3rd table called "ci_nomatch" and contains a reference to ci_address_book.reference
which could have multiple entries (many on many) but I only need the count of that table.
so if ci_address_book would have an entries called "item1","item 2","item3"
and ci_nomatch would have "1,item1,user1","2,item1,user4"
I would like to have returned "2" for Item1 on the query.
Any ideas? I tried another join, but it tells me that the reference does not exist, while it does!
SELECT c.*, IFNULL(p.total, 0) AS matchcount
FROM ci_address_book c
LEFT JOIN (
SELECT addressbook_id, COUNT(match_id) AS total
FROM ci_matched_sanctions
GROUP BY addressbook_id
) AS p
ON c.id=p.addressbook_id
ORDER BY matchcount DESC
LIMIT 0,15
You could subquery it directly in the select
SELECT c.*, IFNULL(p.total, 0) AS matchcount,
(SELECT COUNT(*) FROM ci_nomatch n on n.reference = c.reference) AS othercount
FROM ci_address_book c
LEFT JOIN (
SELECT addressbook_id, COUNT(match_id) AS total
FROM ci_matched_sanctions
GROUP BY addressbook_id
) AS p
ON c.id=p.addressbook_id
ORDER BY matchcount DESC
LIMIT 0,15
#updated for comment. Including an extra column "(matchcount - othercount) AS deducted" would be best done by sub-querying.
SELECT *, matchcount - othercount AS deducted
FROM
(
SELECT c.* , IFNULL( p.total, 0 ) AS matchcount, (
SELECT COUNT( * ) FROM ci_falsepositives n
WHERE n.addressbook_id = c.reference ) AS othercount
FROM ci_address_book c
LEFT JOIN (
SELECT addressbook_id, COUNT( match_id ) AS total
FROM ci_matched_sanctions GROUP BY addressbook_id ) AS p
ON c.id = p.addressbook_id ORDER BY matchcount DESC LIMIT 0 , 15
) S