I have below table
userid comp_dd coursecode qualification course_id course passyear totalmarks func stream
----------- ----------- ----------- --------------- ----------- -------------------------------------------------- ----------- -----------------
60 26 1 High School 15 Class 10 26 67 2 All Subject
60 26 2 Senior Secondry 15 Class 12 26 85 2 Commerce
60 2010 3 Graduates 4 B.Tech/B.E 2010 54 1 IT/Computers
60 2013 4 Post Graduates 9 M.com 2013 98.5 2 Commerce
i wanted to get the unique record of max coursecode, the output should be
userid comp_dd coursecode qualification course_id course passyear totalmarks func stream
----------- ----------- ----------- --------------- ----------- -------------------------------------------------- ----------- -----------------
60 2013 4 Post Graduates 9 M.com 2013 98.5 2 Commerce
There will be many records of the different userids
I think you want:
select t.*
from t
where t.coursecode = (select max(t2.coursecode)
from t t2
where t2.userid = t.userid
);
You can also do this with window functions, but the correlated subquery is often faster with the right index, which would be on (userid, coursecode).
Sort the table by coursecode descending and get the 1st row:
select top 1 *
from tablename
order by coursecode desc
This will work only if there are no duplicates in the column coursecode since it will fetch only 1 row, but I guess this is the case because you say:
i wanted to get the unique record of max coursecode
Related
I need a Statement that selects all patients and the amount of their appointments and when there are 3 or more appointments that are taking place on the same date they should be counted as one appointment
That is what my Statement looks so far
SELECT PATSuchname, Count(DISTINCT AKTDATUM) AS AKTAnz
FROM tblAktivitaeten
LEFT OUTER JOIN tblPatienten ON (tblPatienten.PATID=tblAktivitaeten.PATID)
WHERE (AKTDeleted<>'J' OR AKTDeleted IS Null)
GROUP BY PATSuchname
ORDER BY AKTAnz DESC
The result should look like this
PATSuchname Appointments
----------------------------------------
Joey Patner 13
Billy Jean 15
Example Name 13
As you can see Joey Patner has 13 Appointments, in the real table though he has 15 appointments but three of them have the same Date and because of that they are only counted as 1
So how can i write a Statement that does exactly that?
(I am new to Stack Overflow, sorry if the format I use is wrong and tell me if it is.
In the table it looks like this.
tblPatienten
----------
PATSuchname PATID
------------------------
Joey Patner 1
Billy Jean 2
Example Name 3
tblAktivitaeten
----------
AKTDatum PATID AKTID
-----------------------------------------
08.02.2021 1 1000 ----
08.02.2021 1 1001 ---- So these 3 should counted as 1
08.02.2021 1 1002 ----
09.05.2021 1 1003
09.07.2021 2 1004 -- these 2 shouldn't be counted as 1
09.07.2021 2 1005 --
Two GROUP BY should do it:
SELECT
x.PATID, PATSuchname, SUM(ApptCount)
FROM (
SELECT
PATID, AKTDatum, CASE WHEN COUNT(*) < 3 THEN COUNT(*) ELSE 1 END AS ApptCount
FROM tblAktivitaeten
GROUP BY
PATID, AKTDatum
) AS x
LEFT JOIN tblPatienten ON tblPatienten.PATID = x.PATID
GROUP BY
x.PATID, PATSuchname
So, i have an task in uni to get max stipend in each faculty from a table with stipends.
Faculty table is:
ID_FACULTY FACULTY_NAME DEAN TELEPHON
---------- ------------------------------ -------------------- --------
10 Informacijas tehnologiju Vitols 63023095
11 Lauksaimniecibas Gaile 63022584
12 Tehniska Dukulis 53020762
13 Partikas tehnologijas Sabovics 63021075
Money table is:
ID_PAYOUT STUDENT_ID PAYOUT_DA STIPEND COMPENSATION
---------- ---------- --------- ---------- ------------
100 1 24-SEP-20 45.25 15
101 7 20-SEP-20 149.99 0
102 3 18-SEP-20 100 0
103 17 02-SEP-20 90.85 20
104 9 03-SEP-20 85 20
105 19 09-SEP-20 70.75 0
106 25 15-SEP-20 55 15
107 17 17-SEP-20 105.54 0
108 15 22-SEP-20 94 0
109 27 28-SEP-20 100 20
And the student table is:
ID_STUDENT SURNAME NAME COURSE_YEAR FACULTY_ID BIRTHDATE
---------- ------------------------- -------------------- ----------- ---------- ---------
1 Lapa Juris 4 13 27-SEP-96
3 Vilkauss Fredis 2 10 17-MAY-99
5 Karlsone Rasa 1 11 13-MAR-00
7 Grozitis Guntars 3 12 16-APR-97
9 Sonciks Jurgis 2 10 17-MAR-99
11 Berzajs Olafs 3 10 14-FEB-97
13 Vike Ilvija 2 13 14-MAY-99
15 Baure Inga 3 11 12-APR-97
17 Viskers Zigmunds 2 13 15-AUG-99
19 Talmanis Harijs 3 13 15-JUL-97
21 Livmanis Indulis 1 10 19-JAN-00
23 Shaveja Uva 2 13 18-FEB-98
25 Lacis Guntis 4 10 17-SEP-96
27 Liepa Guna 4 11 18-AUG-96
29 Klava Juris 2 10 19-MAY-98
I have tried many variations of queries, i think that I even tried all the possible combinations of joins, but i cannot achieve the neccessary result.
One of my queries looked like this:
SQL> SELECT ROW_NUMBER() OVER (ORDER BY surname) "Nr.",
f.faculty_name,
s.surname,
s.name,
MAX(m.stipend)
FROM faculty f, student s INNER JOIN money m ON s.id_student = m.student_id
WHERE s.faculty_id = f.id_faculty
GROUP BY f.faculty_name, s.surname, s.name
ORDER BY s.surname;
Which returned me the following result:
Nr. FACULTY_NAME SURNAME NAME MAX(M.STIPEND)
---------- ------------------------------ ------------------------- -------------------- --------------
1 Lauksaimniecibas Baure Inga 94
2 Tehniska Grozitis Guntars 149.99
3 Informacijas tehnologiju Lacis Guntis 55
4 Partikas tehnologijas Lapa Juris 45.25
5 Lauksaimniecibas Liepa Guna 100
6 Informacijas tehnologiju Sonciks Jurgis 85
7 Partikas tehnologijas Talmanis Harijs 70.75
8 Informacijas tehnologiju Vilkauss Fredis 100
9 Partikas tehnologijas Viskers Zigmunds 105.54
9 rows selected.
So the goal of this task is to retrieve the maximum amount of stipend granted to a student in a certain faculty.
Can someone please tell what am I doing wrong here?
Just max amount per faculty:
SELECT
f.faculty_name,
MAX(m.stipend)
FROM
faculty f
INNER JOIN student s ON s.faculty_id = f.id_faculty
INNER JOIN money m ON s.id_student = m.student_id
GROUP BY f.faculty_name
Max amount and all other details too:
SELECT * FROM
(
SELECT
ROW_NUMBER() OVER (PARTITION BY f.faculty_name ORDER BY m.stipend desc) rn,
f.*,
s.*,
m.*
FROM
faculty f
INNER JOIN student s ON s.faculty_id = f.id_faculty
INNER JOIN money m ON s.id_student = m.student_id
) x
WHERE x.rn = 1
Points of note:
Do not use old style joins; if you ever write one table_name, other_table_name in a FROM block, you're using old style joins. Don't do it; they became bad news about 30 years ago
When you have a max-n-per-group, you specify how finely detailed the group is. If you GROUP BY s.first_name, s.last_name, f.faculty_name then your groups are "every unique combination of firstname/lastname/faculty, so the only way you'll get multiple items in your group is if there are two John Smiths in Mathematics. If the group is to be the whole of mathematics, then the faculty name (and anything else that is uniquely related 1:1 to it, like the faculty ID) is all that you can put in your group. Anything not in a group must be in an aggregation, like MAX
When you want other details too, you either group and max the data and then join this groupmaxed data back to the original data to use it as a filter, or you use an approach like here where you use a row_number or rank, with a partition (which is like an autojoined grouped summary). There is no group here; the row numbering acts like a group because it restarts from 1 every different faculty and proceeds incrementally as stipend decreses. This means that the highest stipend is always in row number 1.
Unlike using a groupmax that you join back to get the detail, the row_number route does not produce duplicate rows with tied-for-highest stipends
subject_ID Date Test_id value
------- --------- ----- -----
1 1/1/2000 A 50
1 1/1/2000 B 10
1 1/2/2000 A 55
1 1/2/2000 B 09
2 1/1/2000 A 51
2 1/1/2000 B 13
2 1/2/2000 A 48
2 1/2/2000 B 08
Hi All,
I have a question about the scenario above. As you see I have test results that comes daily for each subjects. I'm trying to find a way to select the lowest value for each test in defined period of time so final table will be like this
subject_ID Date Test_id value
------- --------- ----- -----
1 1/1/2000 A 50
1 1/2/2000 B 09
2 1/2/2000 A 48
2 1/2/2000 B 08
I'm not sure what technology you are using, but assuming SQL something using a GROUP BY will work.
SELECT subject_ID
, Date
, Test_id
, MIN(value)
FROM YourTable
GROUP BY subject_ID
, Date
, Test_id
ANSI standard SQL supports the row_number() function. With this function, you ca do:
select t.*
from (select t.*,
row_number() over (partition by subject_id, test_id order by value asc) as seqnum
from t
) t
where seqnum = 1;
I having trouble with this query
it is executing quit well but I cannot make out
how is this select statement working.
Any help or explanation on this problem will be appreciated ..
thank you
these are my tables and query
here am looking for the employee who lives in same city as the the company for which they work
Table:-emp
eid name street city
----------- ---------------- ------------- ------------
1 yeman asd vasai
2 aksh adssd mumbai
3 chintan ghfgh mumbai
4 samual ghfdgh bandra
5 ddlj fghfgh andheri
6 jack fghnfg Bandra
7 bridge gfhfgh vasai
8 rahim ghfgh mumbai
9 chirag fghfghfg bandra
10 mistry hhhty bandra
11 ravi tytey andheri
Table:- company
cid companyname city
----------- ------------------- ------------
1 Vasai Industries vasai
2 Mumbai Pharmacy mumbai
3 bandra loft bandra
4 andheri tactics andheri
Table:= works
eid cid salary
----------- ----------- -----------
1 1 200
2 3 4831
3 4 4457
4 2 20001
5 1 32221
6 2 224
7 3 784
8 1 336
9 3 2489
10 2 4789
11 1 22541
Query
select * from emp
where eid
IN (select eid from works
where cid=(select cid from company
where city=emp.city))
why not use this query with joins and its easy to understand then a bunch of subqueries.
select * from emp
inner join works on works.eid = emp.eid
inner join company on company.city=emp.city
Explanation:
1.select cid from company where city=emp.city
Here you are getting city id regarding cities which are same in emp and company
2.
select eid from works
where cid=(select cid from company
where city=emp.city)
Here you getting collection of id's from works table which cid is same in emp and company
3.
select * from emp
where eid
IN (select eid from works
where cid=(select cid from company
where city=emp.city))
here you are getting all records based on emp id's whose cities are same in emp and city
I have a table with IDs and primary information. I also have two delta tables keyed on ID and date of change. I need to build a view that merges these three tables together indicating all changes over time.
Main Table:
ID Name
-- ------------------
1 Bob Jones
2 Dave Smith
First Attribute Table:
ID Date Attr1
-- ---------- -----
1 01/01/2013 25
1 02/15/2013 33
1 02/17/2013 47
1 03/02/2013 58
2 02/01/2013 1
...
Second Attribute Table
ID Date Attr2
-- ---------- -----
1 01/01/2013 ABC
1 01/05/2013 DEF
1 01/15/2013 RST
1 02/10/2013 XYZ
1 02/15/2013 Foo
1 03/05/2013 Blah
2 02/01/2013 Two
...
Based on that data, for Bob Jones, I need the view to return the following:
ID Name Date Attr1 Attr2
-- ----------- ---------- ----- -----
1 Bob Jones 01/01/2013 25 ABC
1 Bob Jones 01/05/2013 25 DEF
1 Bob Jones 01/15/2013 25 RST
1 Bob Jones 02/10/2013 25 XYZ
1 Bob Jones 02/15/2013 33 Foo
1 Bob Jones 02/17/2013 47 Foo
1 Bob Jones 03/02/2013 58 Foo
1 Bob Jones 03/05/2013 58 Blah
I tried outer joining the attribute tables to get all change values ordered by date and then used an outer join on the entire query with itself to get "prior" records:
with qry as (
select
rownum = ROW_NUMBER() OVER (ORDER BY m.ID, a.DATE),
m.ID,
m.Name,
a.DATE,
a.Attr1,
a.Attr2
from Main m
inner join (
select
COALESCE(a1.ID, a2.ID) as ID,
COALESCE(a1.LOAD_DATE, a2.LOAD_DATE) as LOAD_DATE,
a1.Attr1,
a2.Attr2
from Attributes1 a1
full outer join Attributes2 a2
on (a1.ID = a2.ID and a1.DATE = a2.DATE)
) a on (a.ID = m.ID)
)
select
COALESCE(qry.ID, prev.ID) as ID,
COALESCE(qry.Name, prev.Name) as Name,
COALESCE(qry.DATE, prev.DATE) as DATE,
COALESCE(qry.Attr1, prev.Attr1) as Attr1,
COALESCE(qry.Attr2, prev.Attr2) as Attr2,
from qry
left join qry prev
on (prev.rownum = qry.rownum - 1)
order by ID, DATE
However, that doesn't work when one attribute table changes quicker than the other because the attributes that didn't change are null in the results of the attribute table join and if two nulls show up back-to-back, the coalesce will return a null when I need the last non-null value that was in that column.
Can this even be done in a view in SQL Server 2012?