Sum of count from external table - sql

I need to search for the sum of the games made by specific developers. I have two tables:
_____________________________
|____________GAMES____________|
| Id | Title | id_dev | hits |
| 01 | abc | 1 | 20 |
| 02 | xyz | 2 | 15 |
| 03 | cde | 1 | 9 |
_______________
|__DEVELOPERS___|
| Id | Title |
| 01 | poi |
| 02 | asd |
| 03 | qwe |
I want result formatted like Developers title 40, where 40 is the sum of all hits of the games with the ID of this developer. How can I go about this?
SELECT developers.title, COUNT(count) AS total FROM (SELECT COUNT(games.hits) AS count
FROM games
GROUP BY id_dev
HAVING count > 1) as A
FROM developers
JOIN games
WHERE developers.id = games.id_dev

This is a simple join and aggregate, so you are overcomplicating things:
select d.id, d.title, sum(g.hits)
from games g join
developers d
on g.id_dev = d.id
group by d.id, d.title;

Related

SQL to Get Latest Field Value

I'm trying to write an SQL query (SQL Server) that returns the latest value of a field from a history table.
The table structure is basically as below:
ISSUE TABLE:
issueid
10
20
30
CHANGEGROUP TABLE:
changegroupid | issueid | updated |
1 | 10 | 01/01/2020 |
2 | 10 | 02/01/2020 |
3 | 10 | 03/01/2020 |
4 | 20 | 05/01/2020 |
5 | 20 | 06/01/2020 |
6 | 20 | 07/01/2020 |
7 | 30 | 04/01/2020 |
8 | 30 | 05/01/2020 |
9 | 30 | 06/01/2020 |
CHANGEITEM TABLE:
changegroupid | field | newvalue |
1 | ONE | 1 |
1 | TWO | A |
1 | THREE | Z |
2 | ONE | J |
2 | ONE | K |
2 | ONE | L |
3 | THREE | K |
3 | ONE | 2 |
3 | ONE | 1 | <--
4 | ONE | 1A |
5 | ONE | 1B |
6 | ONE | 1C | <--
7 | ONE | 1D |
8 | ONE | 1E |
9 | ONE | 1F | <--
EXPECTED RESULT:
issueid | updated | newvalue
10 | 03/01/2020 | 1
20 | 07/01/2020 | 1C
30 | 06/01/2020 | 1F
So each change to an issue item creates 1 change group record with the date the change was made, which can then contain 1 or more change item records.
Each change item shows the field name that was changed and the new value.
I then need to link those tables together to get each issue, the latest value of the field name called 'ONE', and ideally the date of the latest change.
These tables are from Jira, for those familiar with that table structure.
I've been trying to get this to work for a while now, so far I've got this query:
SELECT issuenum, MIN(created) AS updated FROM
(
SELECT ISSUE.IssueId, UpdGrp.Created as Created, UpdItm.NEWVALUE
FROM ISSUE
JOIN ChangeGroup UpdGrp ON (UpdGrp.IssueID = CR.ID)
JOIN CHANGEITEM UpdItm ON (UpdGrp.ID = UpdItm.groupid)
WHERE UPPER(UpdItm.FIELD) = UPPER('ONE')
) AS dummy
GROUP BY issuenum
ORDER BY issuenum
This returns the first 2 columns I'm looking for but I'm struggling to work out how to return the final column as when I include that in the first line I get an error saying "Column is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause."
I've done a search on here and can't find anything that exactly matches my requirements.
Use window functions:
SELECT i.*
FROM (SELECT i.IssueId, cg.Created as Created, ui.NEWVALUE,
ROW_NUMBER() OVER (PARTITION BY i.IssueId ORDER BY cg.Created DESC) as seqnum
FROM ISSUE i JOIN
ChangeGroup cg
ON cg.IssueID = CR.ID JOIN
CHANGEITEM ci
ON cg.ID = ci.groupid
WHERE UPPER(UpdItm.FIELD) = UPPER('ONE')
) i
WHERE seqnum = 1
ORDER BY issueid;

SQL - joining 3 tables and choosing newest logged entry per id

I got rather complicated riddle to solve. So far I'm unlocky.
I got 3 tables which I need to join to get the result.
Most important is that I need highest h_id per p_id. h_id is uniqe entry in log history. And I need newest one for given point (p_id -> num).
Apart from that I need ext and name as well.
history
+----------------+---------+--------+
| h_id | p_id | str_id |
+----------------+---------+--------+
| 1 | 1 | 11 |
| 2 | 5 | 15 |
| 3 | 5 | 23 |
| 4 | 1 | 62 |
+----------------+---------+--------+
point
+----------------+---------+
| p_id | num |
+----------------+---------+
| 1 | 4564 |
| 5 | 3453 |
+----------------+---------+
street
+----------------+---------+-------------+
| str_id | ext | name |
+----------------+---------+-------------+
| 15 | | Mein st. 33 | - bad name
| 11 | | eck st. 42 | - bad name
| 62 | abc | Main st. 33 |
| 23 | efg | Back st. 42 |
+----------------+---------+-------------+
EXPECTED RESULT
+----------------+---------+-------------+-----+
| num | ext | name |h_id |
+----------------+---------+-------------+-----+
| 3453 | efg | Back st. 42 | 3 |
| 4564 | abc | Main st. 33 | 4 |
+----------------+---------+-------------+-----+
I'm using Oracle SQL. Tried using query below but result is not true.
SELECT num, max(name), max(ext), MAX(h_id) maxm FROM history
INNER JOIN street on street.str_id = history._str_id
INNER JOIN point on point.p_id = history.p_id
GROUP BY point.num
In Oracle, you can use keep:
SELECT p.num,
MAX(h.h_id) as maxm,
MAX(s.name) KEEP (DENSE_RANK FIRST ORDER BY h.h_id DESC) as name,
MAX(s.ext) KEEP (DENSE_RANK FIRST ORDER BY h.h_id DESC) as ext
FROM history h INNER JOIN
street s
ON s.str_id = h._str_id INNER JOIN
point p
ON p.p_id = h.p_id
GROUP BY p.num;
The keep syntax allows you to do "first()" and "last()" for aggregations.

How to print the students name in this query?

The concerned tables are as follows:
students(rollno, name, deptcode)
depts(deptcode, deptname)
course(crs_rollno, crs_name, marks)
The query is
Find the name and roll number of the students from each department who obtained
highest total marks in their own department.
Consider:
i) Courses of different department are different.
ii) All students of a particular department take same number and same courses.
Then only the query makes sense.
I wrote a successful query for displaying the maximum total marks by a student in each department.
select do.deptname, max(x.marks) from students so
inner join depts do
on do.deptcode=so.deptcode
inner join(
select s.name as name, d.deptname as deptname, sum(c.marks) as marks from students s
inner join crs_regd c
on s.rollno=c.crs_rollno
inner join depts d
on d.deptcode=s.deptcode
group by s.name,d.deptname) x
on x.name=so.name and x.deptname=do.deptname group by do.deptname;
But as mentioned I need to display the name as well. Accordingly if I include so.name in select list, I need to include it in group by clause and the output is as below:
Kendra Summers Computer Science 274
Stewart Robbins English 80
Cole Page Computer Science 250
Brian Steele English 83
expected output:
Kendra Summers Computer Science 274
Brian Steele English 83
Where is the problem?
I guess this can be easily achieved if you use window function -
select name, deptname, marks
from (select s.name as name, d.deptname as deptname, sum(c.marks) as marks,
row_number() over(partition by d.deptname order by sum(c.marks) desc) rn
from students s
inner join crs_regd c on s.rollno=c.crs_rollno
inner join depts d on d.deptcode=s.deptcode
group by s.name,d.deptname) x
where rn = 1;
To solve the problem with a readable query I had to define a couple of views:
total_marks: For each student the sum of their marks
create view total_marks as select s.deptcode, s.name, s.rollno, sum(c.marks) as total from course c, students s where s.rollno = c.crs_rollno group by s.rollno;
dept_max: For each department the highest total score by a single student of that department
create view dept_max as select deptcode, max(total) max_total from total_marks group by deptcode;
So I can get the desidered output with the query
select a.deptcode, a.rollno, a.name from total_marks a join dept_max b on a.deptcode = b.deptcode and a.total = b.max_total
If you don't want to use views you can replace their selects on the final query, which will result in this:
select a.deptcode, a.rollno, a.name
from
(select s.deptcode, s.name, s.rollno, sum(c.marks) as total from course c, students s where s.rollno = c.crs_rollno group by s.rollno) a
join (select deptcode, max(total) max_total from (select s.deptcode, s.name, s.rollno, sum(c.marks) as total from course c, students s where s.rollno = c.crs_rollno group by s.rollno) a_ group by deptcode) b
on a.deptcode = b.deptcode and a.total = b.max_total
Which I'm sure it is easily improvable in performance by someone more skilled then me...
If you (and anybody else) want to try it the way I did, here is the schema:
create table depts ( deptcode int primary key auto_increment, deptname varchar(20) );
create table students ( rollno int primary key auto_increment, name varchar(20) not null, deptcode int, foreign key (deptcode) references depts(deptcode) );
create table course ( crs_rollno int, crs_name varchar(20), marks int, foreign key (crs_rollno) references students(rollno) );
And here all the entries I inserted:
insert into depts (deptname) values ("Computer Science"),("Biology"),("Fine Arts");
insert into students (name,deptcode) values ("Turing",1),("Jobs",1),("Tanenbaum",1),("Darwin",2),("Mendel",2),("Bernard",2),("Picasso",3),("Monet",3),("Van Gogh",3);
insert into course (crs_rollno,crs_name,marks) values
(1,"Algorithms",25),(1,"Database",28),(1,"Programming",29),(1,"Calculus",30),
(2,"Algorithms",24),(2,"Database",22),(2,"Programming",28),(2,"Calculus",19),
(3,"Algorithms",21),(3,"Database",27),(3,"Programming",23),(3,"Calculus",26),
(4,"Zoology",22),(4,"Botanics",28),(4,"Chemistry",30),(4,"Anatomy",25),(4,"Pharmacology",27),
(5,"Zoology",29),(5,"Botanics",27),(5,"Chemistry",26),(5,"Anatomy",25),(5,"Pharmacology",24),
(6,"Zoology",18),(6,"Botanics",19),(6,"Chemistry",22),(6,"Anatomy",23),(6,"Pharmacology",24),
(7,"Sculpture",26),(7,"History",25),(7,"Painting",30),
(8,"Sculpture",29),(8,"History",24),(8,"Painting",30),
(9,"Sculpture",21),(9,"History",19),(9,"Painting",25) ;
Those inserts will load these data:
select * from depts;
+----------+------------------+
| deptcode | deptname |
+----------+------------------+
| 1 | Computer Science |
| 2 | Biology |
| 3 | Fine Arts |
+----------+------------------+
select * from students;
+--------+-----------+----------+
| rollno | name | deptcode |
+--------+-----------+----------+
| 1 | Turing | 1 |
| 2 | Jobs | 1 |
| 3 | Tanenbaum | 1 |
| 4 | Darwin | 2 |
| 5 | Mendel | 2 |
| 6 | Bernard | 2 |
| 7 | Picasso | 3 |
| 8 | Monet | 3 |
| 9 | Van Gogh | 3 |
+--------+-----------+----------+
select * from course;
+------------+--------------+-------+
| crs_rollno | crs_name | marks |
+------------+--------------+-------+
| 1 | Algorithms | 25 |
| 1 | Database | 28 |
| 1 | Programming | 29 |
| 1 | Calculus | 30 |
| 2 | Algorithms | 24 |
| 2 | Database | 22 |
| 2 | Programming | 28 |
| 2 | Calculus | 19 |
| 3 | Algorithms | 21 |
| 3 | Database | 27 |
| 3 | Programming | 23 |
| 3 | Calculus | 26 |
| 4 | Zoology | 22 |
| 4 | Botanics | 28 |
| 4 | Chemistry | 30 |
| 4 | Anatomy | 25 |
| 4 | Pharmacology | 27 |
| 5 | Zoology | 29 |
| 5 | Botanics | 27 |
| 5 | Chemistry | 26 |
| 5 | Anatomy | 25 |
| 5 | Pharmacology | 24 |
| 6 | Zoology | 18 |
| 6 | Botanics | 19 |
| 6 | Chemistry | 22 |
| 6 | Anatomy | 23 |
| 6 | Pharmacology | 24 |
| 7 | Sculpture | 26 |
| 7 | History | 25 |
| 7 | Painting | 30 |
| 8 | Sculpture | 29 |
| 8 | History | 24 |
| 8 | Painting | 30 |
| 9 | Sculpture | 21 |
| 9 | History | 19 |
| 9 | Painting | 25 |
+------------+--------------+-------+
I take chance to point out that this database is badly designed. This becomes evident with course table. For these reasons:
The name is singular
This table does not represent courses, but rather exams or scores
crs_name should be a foreign key referencing the primary key of another table (that would actually represent the courses)
There is no constrains to limit the marks to a range and to avoid a student to take twice the same exam
I find more logical to associate courses to departments, instead of student to departments (this way also would make these queries easier)
I tell you this because I understood you are learning from a book, so unless the book at one point says "this database is poorly designed", do not take this exercise as example to design your own!
Anyway, if you manually resolve the query with my data you will come to this results:
+----------+--------+---------+
| deptcode | rollno | name |
+----------+--------+---------+
| 1 | 1 | Turing |
| 2 | 6 | Bernard |
| 3 | 8 | Monet |
+----------+--------+---------+
As further reference, here the contents of the views I needed to define:
select * from total_marks;
+----------+-----------+--------+-------+
| deptcode | name | rollno | total |
+----------+-----------+--------+-------+
| 1 | Turing | 1 | 112 |
| 1 | Jobs | 2 | 93 |
| 1 | Tanenbaum | 3 | 97 |
| 2 | Darwin | 4 | 132 |
| 2 | Mendel | 5 | 131 |
| 2 | Bernard | 6 | 136 |
| 3 | Picasso | 7 | 81 |
| 3 | Monet | 8 | 83 |
| 3 | Van Gogh | 9 | 65 |
+----------+-----------+--------+-------+
select * from dept_max;
+----------+-----------+
| deptcode | max_total |
+----------+-----------+
| 1 | 112 |
| 2 | 136 |
| 3 | 83 |
+----------+-----------+
Hope I helped!
Try the following query
select a.name, b.deptname,c.marks
from students a
, crs_regd b
, depts c
where a.rollno = b.crs_rollno
and a.deptcode = c.deptcode
and(c.deptname,b.marks) in (select do.deptname, max(x.marks)
from students so
inner join depts do
on do.deptcode=so.deptcode
inner join (select s.name as name
, d.deptname as deptname
, sum(c.marks) as marks
from students s
inner join crs_regd c
on s.rollno=c.crs_rollno
inner join depts d
on d.deptcode=s.deptcode
group by s.name,d.deptname) x
on x.name=so.name
and x.deptname=do.deptname
group by do.deptname
)
Inner/Sub query will fetch the course name and max marks and the outer query gets the corresponding name of the student.
try and let know if you got the desired result
Dense_Rank() function would be helpful in this scenario:
SELECT subquery.*
FROM (SELECT Student_Total_Marks.rollno,
Student_Total_Marks.name,
Student_Total_Marks.deptcode, depts.deptname,
rank() over (partition by deptcode order by total_marks desc) Student_Rank
FROM (SELECT Stud.rollno,
Stud.name,
Stud.deptcode,
sum(course.marks) total_marks
FROM students stud inner join course course on stud.rollno = course.crs_rollno
GROUP BY stud.rollno,Stud.name,Stud.deptcode) Student_Total_Marks,
dept dept
WHERE Student_Total_Marks.deptcode = dept.deptname
GROUP BY Student_Total_Marks.deptcode) subquery
WHERE suquery.student_rank = 1

SQL: Cascading conditions on Join

I have found a few similar questions to this on SO but nothing which applies to my situation.
I have a large dataset with hundreds of millions of rows in Table 1 and am looking for the most efficient way to run the following query. I am using Google BigQuery but I think this is a general SQL question applicable to any DBMS?
I need to apply an owner to every row in Table 1. I want to join in the following priority:
1: if item_id matches an identifier in Table 2
2: if no item_id matches try match on item_name
3: if no item_id or item_name matches try match on item_division
4: if no item_division matches, return null
Table 1 - Datapoints:
| id | item_id | item_name | item_division | units | revenue
|----|---------|-----------|---------------|-------|---------
| 1 | xyz | pen | UK | 10 | 100
| 2 | pqr | cat | US | 15 | 120
| 3 | asd | dog | US | 12 | 105
| 4 | xcv | hat | UK | 11 | 140
| 5 | bnm | cow | UK | 14 | 150
Table 2 - Identifiers:
| id | type | code | owner |
|----|---------|-----------|-------|
| 1 | id | xyz | bob |
| 2 | name | cat | dave |
| 3 | division| UK | alice |
| 4 | name | pen | erica |
| 5 | id | xcv | fred |
Desired output:
| id | item_id | item_name | item_division | units | revenue | owner |
|----|---------|-----------|---------------|-------|---------|-------|
| 1 | xyz | pen | UK | 10 | 100 | bob | <- id
| 2 | pqr | cat | US | 15 | 120 | dave | <- code
| 3 | asd | dog | US | 12 | 105 | null | <- none
| 4 | xcv | hat | UK | 11 | 140 | fred | <- id
| 5 | bnm | cow | UK | 14 | 150 | alice | <- division
My attempts so far have involved multiple joining the table onto itself and I fear it is becoming hugely inefficient.
Any help much appreciated.
Another option for BigQuery Standard SQL
#standardSQL
SELECT ARRAY_AGG(a)[OFFSET(0)].*,
ARRAY_AGG(owner
ORDER BY CASE
WHEN type = 'id' THEN 1
WHEN type = 'name' THEN 2
WHEN type = 'division' THEN 3
END
LIMIT 1
)[OFFSET(0)] owner
FROM Datapoints a
JOIN Identifiers b
ON (a.item_id = b.code AND b.type = 'id')
OR (a.item_name = b.code AND b.type = 'name')
OR (a.item_division = b.code AND b.type = 'division')
GROUP BY a.id
ORDER BY a.id
It leaves out entries which k=have no owners - like in below result (id=3 is out as it has no owner)
Row id item_id item_name item_division units revenue owner
1 1 xyz pen UK 10 100 bob
2 2 pqr cat US 15 120 dave
3 4 xcv hat UK 11 140 fred
4 5 bnm cow UK 14 150 alice
I am using the following query (thanks #Barmar) but want to know if there is a more efficient way in Google BigQuery:
SELECT a.*, COALESCE(b.owner,c.owner,d.owner) owner FROM datapoints a
LEFT JOIN identifiers b on a.item_id = b.code and b.type = 'id'
LEFT JOIN identifiers c on a.item_name = c.code and c.type = 'name'
LEFT JOIN identifiers d on a.item_division = d.code and d.type = 'division'
I'm not sure if BigQuery optimizes today a query like this - but at least you would be writing a query that gives strong hints to not run the subqueries when not needed:
#standardSQL
SELECT COALESCE(
null
, (SELECT MIN(payload)
FROM `githubarchive.year.2016`
WHERE actor.login=a.user)
, (SELECT MIN(payload)
FROM `githubarchive.year.2016`
WHERE actor.id = SAFE_CAST(user AS INT64))
)
FROM (SELECT '15229281' user) a
4.2s elapsed, 683 GB processed
{"action":"started"}
For example, the following query took a long time to run, but BigQuery could optimize its execution massively in the future (depending on how frequently users needed an operation like this):
#standardSQL
SELECT COALESCE(
"hello"
, (SELECT MIN(payload)
FROM `githubarchive.year.2016`
WHERE actor.login=a.user)
, (SELECT MIN(payload)
FROM `githubarchive.year.2016`
WHERE actor.id = SAFE_CAST(user AS INT64))
)
FROM (SELECT actor.login user FROM `githubarchive.year.2016` LIMIT 10) a
114.7s elapsed, 683 GB processed
hello
hello
hello
hello
hello
hello
hello
hello
hello
hello

SQL Server: how do I get data from a history table?

Can you please help me build an SQL query to retrieve data from a history table?
I'm a newbie with only a one-week coding experience. I've been trying simple SELECT statements so far but have hit a stumbling block.
My football club's database has three tables. The first one links balls to players:
BallDetail
| BallID | PlayerID | TeamID |
|-------------------|--------|
| 1 | 11 | 21 |
| 2 | 12 | 22 |
The second one lists things that happen to the balls:
BallEventHistory
| BallID | Event | EventDate |
|--------|------ |------------|
| 1 | Pass | 2012-01-01 |
| 1 | Shoot | 2012-02-01 |
| 1 | Miss | 2012-03-01 |
| 2 | Pass | 2012-01-01 |
| 2 | Shoot | 2012-02-01 |
And the third one is a history change table. After a ball changes hands, history is recorded:
HistoryChanges
| BallID | ColumnName | ValueOld | ValueNew |
|--------|------------|----------|----------|
| 2 | PlayerID | 11 | 12 |
| 2 | TeamID | 21 | 22 |
I'm trying to obtain a table that would list all passes and shoots Player 11 had done to all balls before the balls went to other players. Like this:
| PlayerID | BallID | Event | Month |
|----------|--------|-------|-------|
| 11 | 1 | Pass | Jan |
| 11 | 1 | Shoot | Feb |
| 11 | 2 | Pass | Jan |
I begin so:
SELECT PlayerID, BallID, Event, DateName(month, EventDate)
FROM BallDetail bd INNER JOIN BallEventHistory beh ON bd.BallID = beh.BallID
WHERE PlayerID = 11 AND Event IN (Pass, Shoot) ...
But how to make sure that Ball 2 also gets included despite being with another player now?
Select PlayerID,BallID,Event,datename(month,EventDate) as Month,Count(*) as cnt from
(
Select
Coalesce(
(Select ValueNew from #HistoryChanges where ChangeDate=(Select max(ChangeDate) from #HistoryChanges h2 where h2.BallID=h.BallID and ColumnName='PlayerID' and ChangeDate<=EventDate) and BallID=h.BallID and ColumnName='PlayerID')
,(Select PlayerID from #BallDetail where BallID=h.BallID)
) as PlayerID,
h.BallID,h.Event,EventDate
from #BallEventHistory h
) a
Group by PlayerID, BallID, Event,datename(month,EventDate)
SELECT d.PlayerID, d.BallID, h.Event, DATENAME(mm, h.EventDate) AS Month
FROM BallDetail d JOIN BallEventHistory h ON d.BallID = h.BallID
WHERE h.Event IN ('Pass', 'Shoot') AND d.PlayerID = 11
OR EXISTS (SELECT 1
FROM dbo.HistoryChanges c
WHERE c.ValueOld = 11 AND c.ValueNew = d.PlayerID AND c.ColumnName = 'PlayerID' and c.ChangeDate = h.EventDate)