I have two tables I want to display student without results
Student tables
Sname snumber
A 1
B 2
C 3
G 4
And results table
Snumber marks
1 90
4 60
I have the following code
Select student.sname from student
Join results
On student.snumber=results.snumber
Its showing students With results. I want student without results which is B and C
Try this,
Select student.sname
from student
LEFT Join results
On student.snumber=results.snumber
WHERE results.snumber is null
If you want all the students then remove the where clause.
After LEFT JOIN solution (#Jatin Patel), you can see NOT EXISTS one:
SELECT *
FROM Students S
WHERE NOT EXISTS(SELECT * FROM results R WHERE S.snumber=R.snumber)
Related
I have a table with student info [STU] and a table with parent info [PAR]. I want to return an email address for each student, but just one. So I run this query:
SELECT [STU].[ID], [PAR].[EM]
FROM (SELECT [STU].* FROM DB1.STU)
STU LEFT JOIN (SELECT [PAR].* FROM DB1.PAR) PAR ON [STU].[ID] = [PAR].[ID]
This gives me the below table:
Student ID ParentEmail
1 jim#email.com
1 sarah#email.com
2 paul#email.com
2 tim#email.com
3 bill#email.com
3 frank#email.com
3 joyce#email.com
4 greg#email.com
5 tony#email.com
5 sam#email.com
Each student has multiple parent emails, but I only want one. In other words, I want the output to look like this:
Student ID ParentEmail
1 jim#email.com
2 paul#email.com
3 frank#email.com
4 greg#email.com
5 sam#email.com
I've tried so many things. I've tried using GROUP BY and MIN/MAX and I've tried complex CASE statements, and I've tried COALESCE but I just can't seem to figure it out.
I think OUTER APPLY is the simplest method:
SELECT [STU].[ID], [PAR].[EM]
FROM DB1.STU OUTER APPLY
(SELECT TOP (1) [PAR].*
FROM DB1.PAR
WHERE [STU].[ID] = [PAR].[ID]
) PAR;
Normally, there would be an ORDER BY in the subquery, to give you control over which email you want -- the longest, shortest, oldest, or whatever. Without an ORDER BY it returns just one email, which is what you are asking for.
If you just want one column from the parent table, a simple approach is a correlated subquery:
select
s.id student_id,
(select max(p.em) from db1.par p where p.id = s.id) parent_email
from db1.stu s
This gives you the greatest parent email per student.
I have two tables one is teacher and another is Department which is mentioned below.
Teacher Table
Id Name
1 xyz
2. Gjd
3. Dftr
4 dhdk
Department Table
Id Name EMPID
1 SQL. 2
2. PHP. 4
3. JAVA. 1
4 PEARL. 5
QUESTION
i want those records of teacher which are not link with any Department.
you can use following statement using left join then filter Teacher that not matched
SELECT t.*
FROM Teacher t
left join Department d on d.EMPID = t.Id
where d.id is null
SELECT * FROM teachers WHERE
id NOT IN (SELECT DISTINCT EMPID FROM departments) ;
Hope this helps.!!
you can do it by inner query..
select * from teacher where id not in (select empid from department);
Here I have two tables committee_colleges and colleges.
Structure of tables is something like this
committee_colleges
committeeCollegeId collegeId committeeMemberId
1 2 1
2 2 2
3 3 2
I am storing committeeMemberId from committeeMember table.And one college can have multiple committee Members.How can I wite a query to display only the colleges assigned to specific committee Member.
For Example,if committeeMember by id=2 has logged in I want to display colleges by id=2,3.
In college table I have like this,
collegeId typeName
1 AICTE
2 NCTE
3 NTCS
This is Committee Member table
committeeMemberId name
1 xyz
2 abc
Now I am writing something like this,but i know its wrong because I dont know how to take it from College table since I am displaying College details.
SELECT cc.committeeCollegeId as committeeCollegeId,
c.collegeId as collegeId,
cc.committeeMemberId as committeeMemberId
FROM committee_college as cc
left outer join College as c
on cc.collegeId = c.collegeId
where cc.committeeMemberId=:committeeMemberId
order by cc.committeeCollegeId asc
Can anyone tell how to display colleges based on its assignment to particular committeeMember?
You were close, you need INNER JOIN instead of LEFT JOIN:
SELECT DISTINCT C.typeName --<<== put here all the columns that you want in output
FROM committee_colleges CC
INNER JOIN college C
ON C.collegeId = CC.collegeId
WHERE CC.committeeMemberId = 2 --<<== your input parameter
EDIT: added DISTINCT
Hope it helps.
You can use below sql statement for the same
DECLARE #committeeMemberId INT = 2 -- Id of Committee member
;WITH CTE_MemberCommittee AS
(
SELECT CollegeId
FROM committee_colleges
WHERE committeeMemberId = #committeeMemberId
)
SELECT collegeId, typeName
FROM college
WHERE collegeId IN (SELECT CollegeId FROM CTE_MemberCommittee)
You can use simple inner join for that,
If you want collegename based on memberId use following query,
select a.collegeid,a.typeName from
college a, committee_colleges b, committe_member c
where a.collegeid = b.collegeid and
b.committeememberid = c.committeeMemberId
and c.committeeMemberId = '2'
If you want collegename based on committemember name then use following query,
select a.collegeid,a.typeName from
college a, committee_colleges b, committe_member c
where a.collegeid = b.collegeid and
b.committeememberid = c.committeeMemberId
and c.Name = 'xyz'
Hope it will help.
try this:
DECLARE #LoginCommitteeMemberId INT=2
SELECT t2.Name AS MemberName,
t3.TypeName AS CollageName
FROM committee_college t1
INNER JOIN Committee_Member t2
ON t1.committeeMemberId = t2.committeeMemberId
INNER JOIN College as t3
ON t1.collegeId = t3.collegeId
WHERE t1.committeeMemberId = #LoginCommitteeMemberId
A Pupil table with { ID, LastName}
a Subject Table with {ID, SubjectName}
and a Report Table with {ID, PupilID, SubjectID, Grade}
There is a one-to-many relationship between Pupil and Report Tables, and Subject and Report Tables.
I want to generate a table like this for say subjectID = 1
Pupil.ID Pupil.LastName SubjectID Grade
1 --------------Smith ---------- 1 ------------B
2 --------------Jones ---------- 1 ------------NULL
3 -------------Weston ----------1 ------------NULL
4 -------------Knightly ---------1 -----------A
The problem is that the Report table would contain just 2 entries for subject 1:
PupilID SubjectID Grade
----1------- 1 ----------- B
----4------- 1 ----------- A
Left joins don't seem to work since there are only 2 entries in the report table for subject 1
SAMPLE DATA
{Pupil Table}
ID LastName
1 ...Smith
2 ...Jones
3 ...Weston
4 ...Knightly
{Subject Table}
ID SubjectName
1 ....Maths
2 ....Physics
3 ....Chemistry
{Report Table}
ID PupilID SubjectID Grade
1 .......1 ..........1 ..........B
2 .......4 ..........1 ..........A
When I do a search on SubjectID = 1 I want the table:
Pupil.ID .......Pupil.LastName ........SubjectID ...........Grade
1 --------------Smith ---------- 1 ------------B
2 --------------Jones ---------- 1 ------------NULL
3 -------------Weston ----------1 ------------NULL
4 -------------Knightly ---------1 -----------A
Access doesn't do subqueries very easily, so everything gets crammed into the FROM clause with a series of wrapped parentheses. Based on your sample data and my fighting Access to stop being unnecessarily difficult, I came up with this:
SELECT ps.Pupil_ID, ps.LastName, ps.Subject_ID, r.Grade
FROM (SELECT * FROM (SELECT ID AS Pupil_ID, LastName FROM Pupil) p,
(SELECT DISTINCT ID AS Subject_ID FROM Subject)) ps
LEFT JOIN REPORT r ON r.PupilID = ps.Pupil_ID AND r.SubjectID = ps.Subject_ID
ORDER BY Pupil_ID, Subject_ID;
The subquery "ps" is a cartesian join of the Pupil and Subject table views that I specified. At this point, your query would look like this:
(LastName column not shown for clarity)
StudentID|SubjectID
1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3
Now, using that Cartesian join subquery (pupilstudent -> ps), I use a LEFT JOIN to assign the Report table to each unique student's ID and subject ID. Therefore, if a student did not take a particular class, there will be a NULL value in the final result.
I tested this in Access using your sample data and it works on my machine.
Also as a note, it is poor practice to have a field called just ID in each table (e.g. in the Pupil table, ID becomes PupilID). This makes it much easier to use, and it self documents.
Cross join pupil and subject tables and left join result to report table
What you need is a cross join:
SELECT Pupil.ID, Pupil.LastName, SubjectID, Grade FROM
Pupil, Subject LEFT JOIN Report ON Subject.ID=Report.SubjectID
WHERE Subject.ID=1
To combine every pupil with every (or with a particular) subject, use cross join; Then use left join to get the corresponding grades:
select *
from pupil p cross join (select * from subject where id = 1) s
left join report on subjectId = s.id and pupilId = p.id
Here is the case:
There is a user table
id email orders_counter
=================================
1 a#a.com 5
2 b#b.com 3
3 c#c.com 0
And a user data table for user's other data
id user_id title value
=======================================
1 1 Name Peter Johnson
2 1 Tel 31546988
3 2 Name Alan Johnson
4 2 Tel 56984887
If I want to fetch all user that
1, orders_counter greater then 3
2, Name contain 'Johnson'
3, Tel contain '88'
AT THE SAME TIME
What is my sql, and if I want to do it rubyonrails way
what is the ActiveRecord code
I know I can it one by one and then join all of them together, but it waste too much resource while conditions build up
Select * From `user` u
inner join `userdata` d on d.user_id=u.id and d.title='Name' and d.value like '%Johnson%'
inner join `userdata` c on c.user_id=u.id and c.title='Tel' and c.value like '%88%'
where orders_counter > 3
the way that you've got your user data table structured, you'll almost always have to join on that table several times in order to "pivot" those values into columns. I'd recommend just creating a table that has name and tel as columns. then the query becomes a lot more simple
select * from `user` u
inner join `user_data` d on d.Tel like '%88%' and d.Name like '%johnson%'
where u.orders_counter > 3
try this one up,
SELECT a.*, b.*
FROM user a
INNER JOIN data b
ON a.id = b.user_ID
WHERE a.orders_counter > 3 AND
(b.title = 'NAME' AND b.value like '%johnson%') AND
(b.title = 'TEL' AND b.tel like '%88%')
try this:
select *
from user U join user_data D
on U.id=D.user_id
where U.orders_counter>3
and D.title='Name' and value like '%Johnson%'
and D.title='Tel' and value like '%88%'