I have in my table, say thousands of records. I want to display records together by city. It's a lot more complicated then that, since I need it displayed in alphabetical order as well based on customer name. How do I achieve this? Group BY seems to want to give me a total instead of displaying each of my records. so..
mark zuck some city
john smith cherryville
bill gates some city
jane doe cherryville
should return
bill gates some city
mark zuck some city
jane doe cherryville
john smith cherryville
This is an over-simplification but the idea stands. I appreciate all the help. thank you!
Group by is for aggregations. There is no aggregation in your query. You just want your output to be sorted. In this case, Order By well fits for the purpose.
select * from table1
order by city, customer
In english, get all table1 data sorted by first city, then customer
Related
I have the following data:
CompanyID
Department
No of People
Country
45390
HR
100
UK
45390
Service
250
UK
98712
Service
300
US
39284
Admin
142
Norway
85932
Admin
260
Germany
I wish to know how many people belong to the same department from different countries?
Required Output
Department
No of People
Country
HR
100
UK
Service
250
UK
300
US
Admin
142
Norway
260
Germany
I was able to get the data but the Department was repeated by this query.
""" select Department, Country,count(Department) from dataset
group by Country,Department
order by Department """
How can I get the desired output?
The result set that you are producing is not really a relational result set. Why? Because rows depend on what is in the "previous" row. And in a relational database, there is no such thing as a "previous" row. This type of processing is often handled in the application layer.
Of course, SQL can do what you want. You just need to be careful:
select (case when 1 = row_number() over (partition by Department order by Country)
then Department
end) as Department,
Country, count(*) as num_people,
from dataset
group by Country,Department
order by Department, Country;
Note that the order by needs to match the window function clause to be sure that what row_number() considered to be the first row is really the first row in the result set.
Not sure how to describe this, but I want to group a row of values, where one field has two or more different values and set the value of that (but concatenating or changing the values) to give just one single row.
For example:
I have a simple table (all fields are Strings) of people next to their departments. But some people belong to more than one department.
select department_ind, name
from jobs
;
department_ind name
1 Michael
2 Michael
2 Sarah
3 Dave
2 Sally
4 Sally
I want to group by name, and concatenate the department_ind. So the results show look like:
department_ind name
1,2 Michael
2 Sarah
3 Dave
2,4 Sally
Thanks
Use string_agg()
select string_agg(department_ind::text, ',') as departments,
name
from jobs
group by name;
Looking into my notes for introduction to databases, I have stumbled upon a case that i do not understand (Between except and distinct).
It says so in my notes that:
The two queries below have the same results, but this will not be the case in general.
First query:
Select c.first_name,c.last_name,c.email
FROM customers as c
WHERE c.country = 'Japan'
EXCEPT
Select c.first_name,c.last_name,c.email
FROM customers as c
WHERE c.last_name LIKE 'D%';
Second query:
Select DISTINCT c.first_name,c.last_name,c.email
FROM customers as c
WHERE c.country = 'Japan' AND NOT (c.last_name LIKE 'D%');
Could anyone provide me some insights as to what are cases whereby the results would differ?
Number 1 selects first, last & email from customers who are from Japan and whose last names do not start with D.
Number 2 selects first, last & email, where no two records have all 3 fields the same, where the customers are from Singapore and their last names do not begin with D.
I suppose I can imagine a table where these would yield the same results, but I don't think it would ever appear except in very contrived circumstances.
Joe Smith jsmith#abc.com Japan
Joe Smith jsmith#abc.com Singapore
Would be one of them. Both queries would yield Joe Smith jsmith#abc.com. Another case would be if no-one was from either country or everyone's last name started with D, then they would both yield nothing.
None of this is tested, and the EXCEPT statement is something I've read about but never had occasion to use.
The first is looking at Japan, the second at Singapore, so I don't see why these would generally -- or specifically -- return the same data.
Even if the countries were the same you have another issue with NULL values. So, if your data looks like this:
first_name last_name email country
xxx NULL a Japan
Your first query would return the row. The second would not.
Due to the way a particular table is written I need to do something a little strange in SQL and I can't find a 'simple' way to do this
Table
Name Place Amount
Chris Scotland
Chris £1
Amy England
Amy £5
Output
Chris Scotland £1
Amy England £5
What I am trying to do is above, so the null rows are essentially ignored and 'grouped' up based on the Name
I have this working using For XML however it is incredibly slow, is there a smarter way to do this?
This is where MAX would work
select
Name
,Place = Max(Place)
,Amount = Max(Amount)
from
YourTable
group by
Name
Naturally, if you have more than one occurance of a place for a given name, you may get unexpected results.
I'm trying to solve this query where i need to find the the top balance at each base. Balance is in one table and bases are in another table.
This is the existing query i have that returns all the results but i need to find a way to limit it to 1 top result per baseID.
SELECT o.names.name t.accounts.bidd.baseID, MAX(t.accounts.balance)
FROM order o, table(c.accounts) t
WHERE t.accounts.acctype = 'verified'
GROUP BY o.names.name, t.accounts.bidd.baseID;
accounts is a nested table.
this is the output
Name accounts.BIDD.baseID MAX(T.accounts.BALANCE)
--------------- ------------------------- ---------------------------
Jerard 010 1251.21
john 012 3122.2
susan 012 3022.2
fin 012 3022.2
dan 010 1751.21
What i want the result to display is calculate the highest balance for each baseID and only display one record for that baseID.
So the output would look only display john for baseID 012 because he has the highest.
Any pointers in the right direction would be fantastic.
I think the problem is cause of the "Name" column. since you have three names mapped to one base id(12), it is considering all three records as unique ones and grouping them individually and not together.
Try to ignore the "Name" column in select query and in the "Group-by" clause.
SELECT t.accounts.bidd.baseID, MAX(t.accounts.balance)
FROM order o, table(c.accounts) t
WHERE t.accounts.acctype = 'verified'
GROUP BY t.accounts.bidd.baseID;