Count and max (id) in single query

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Hi,

I have a mysql table structure like below:

id, name, city
----------------
1, name1, city1
2, name2, city2
3, name3, city1
4, name4, city1,
5, name5, city2

I want to fetch total rows with max row id for a particular city.

Ex. For city = "city1"
Output should be:

totalrows, max(id), name
3, 4, name4

Ex. For city = "city2"
Output should be:

totalrows, max(id), name
2, 5, name5

How can I get this result in a single query?

What I have tried:

I did tried my self many query but unable to find any query and finally submit the question here.

Posted 18-Jun-17 7:47am

kals84

Updated 19-Jun-17 13:11pm

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CHill60 · Answer 1 · 2017-06-18T10:57:00

You need to use group by to get the initial data and then you can put all of that into a sub-query. The following example is in T-SQL and was tested against SQL Server as I am unable to load MySQL at this time. The syntax may have some minor errors but the principal works:

I created a table called kals84 with your data as per the question and this query returns the values you require:

SQL

select q.cnt, q.mx, k.name, q.city
from kals84 k
inner join (select city, count(*) as cnt, max(id) as mx
from kals84 group by city) q on k.city = q.city and q.mx = k.id

The key to this working is the sub-query

SQL

select city, count(*) as cnt, max(id) as mx
from kals84 group by city

which returns the values

city   cnt      mx
city1	3	4
city2	2	5

You get the name from joining to those results based on the city and the derived mx column

AlwzLearning · Answer 2 · 2017-06-19T13:11:00

Solution 2

select distinct Count(Id) over (partition by city) as "Total_rows" ,Max(id) over (partition by city) as "max_id", name
from temp_cp

Posted 19-Jun-17 13:11pm

AlwzLearning