Ok I have two tables.
One table is called Persons and just has columns Pname and Age. (A person's name and their age).
Another table is called Giving and has donor, receiver, and giftname. (donor and receiver have foreign key constraints referencing persons.pname).
I need to find the names of all people who donated a gift to someone with a different age.
SELECT
Giving.donor
FROM Giving
INNER JOIN Persons AS donor ON Giving.donor=donor.Pname
INNER JOIN Persons AS receiver ON Giving.receiver=receiver.Pname
WHERE donor.Age<>receiver.Age
If you mean the donor age has to be different then the receiver age, then try this:
SELECT pd.pname
FROM Persons pd
INNER JOIN giving g
ON pd.pname = g.donor
INNER JOIN persons pr
ON pr.pname = g.receiver AND pr.age != pd.age
Related
I have 2 tables: Person and House with 1-n relation.
I want to the result return as picture below:
Row always have a Person column with a null House column.
Thanks.
you can use unionall to join the result set with person table something like
select p.name,h.name as housename from person p join house h on p.id=h.personid
union all (select name,null from person)
order by name,housename
I want to pull a person and their supervisor names from a table. The persons table has the supervisor_id and the person_id. The names table has name_id and a Full Name field. If I join Person ON either supervisor_id or person_id, how do I get the other to display as well?
You need to join twice, one for each relationship you have:
SELECT
-- Persons' columns
P.*,
-- Superviser name columns
SN.*,
-- Person name columns
PN.*
FROM
persons AS P
LEFT JOIN names AS SN ON P.supervisor_id = SN.name_id
LEFT JOIN names AS PN ON P.person_id = PN.name_id
Or you can join with an OR clause, but you won't be able to know which record did you join with unless you check with a CASE.
SELECT
-- Persons' columns
P.*,
-- name columns
N.*,
IsSupervisor = CASE WHEN P.supervisor_id = N.name_id THEN 'Yes' ELSE 'No' END
FROM
persons AS P
LEFT JOIN names AS N ON
P.supervisor_id = N.name_id OR
P.person_id = N.name_id
This last approach will display 2 rows as it will match either one or the other on different occasions, not both with the same persons row (as the first example).
A (self)join is what you need:
select p.*, supervisor=ps.name
from Person p join person ps on p.supervisor_id=ps.id
I have one table name Class_sub where I have subjects name according to the classes, I have weekly_test table where the same subject's marks have to be entered.
My problem is to show subject name as field name in weekly_test table reference to class_sub table data fields.
If you have the following tables:
CLASS
id
name
SUBJECT
id
name
CLASS_SUBJECT
id
class_id
subject_id
WEEKLY_MARKS
id
class_subject_id
test_date
mark
The following query will work:
SELECT s.name as subject_name,
c.name as class_name,
wm.test_date,
wm.mark
FROM weekly_marks wm
INNER JOIN class_subject cs ON wm.class_subject_id = cs.id
INNER JOIN class c ON cs.class_id = c.id
INNER JOIN subject s ON cs.subject_id = s.id
A bit of a guess here, but assuming the class_subject table you're talking about is joining of subjects (students?) to the classes they are enrolled in.
I need to display two columns from my attendance table (MEMBER_ID & MEETING_ID) and one column from my meeting table and finally two columns from my member table which displays the names that match with MEETING_ID.
The attendance table has a composite key (MEMBER_ID*, MEETING_ID*)
The member table's primary key is MEMBER_ID
Meeting table's primary key is MEETING_ID
My attempt is not working, can someone please help?
SELECT MEMBER_ID, MEETING_ID, MEETING_NAME MEMBER_FIRSTNAME, MEMBER_LASTNAME
FROM ATTENDANCE, MEMBER, MEETING
WHERE MEETING.MEMBER_ID = MEETING.MEMBER_ID;
End result needs to be:
MEMBER_ID MEETING_ID MEETING_NAME FIRSTNAME LASTNAME
0001 MEET0004 SPORTS DAY JOHN SMITH
May be you need this.
SELECT A.MEMBER_ID, A.MEETING_ID, M2.MEETING_NAME, M1.MEMBER_FIRSTNAME, M1.MEMBER_LASTNAME
FROM ATTENDANCE A, MEMBER M1, MEETING M2
WHERE M1.MEMBER_ID = A.MEMBER_ID
AND A.MEETING_ID = M2.MEETING_ID;
SELECT
a.MEMBER_ID
,a.MEETING_ID
,mt.MEETING_NAME
,mb.MEMBER_FIRSTNAME
,mb.MEMBER_LASTNAME
FROM
ATTENDANCE a
INNER JOIN MEMBER mb
ON a.MEMBER_ID = mb.MEMBER_ID
INNER JOIN MEETING mt
ON a.MEETING_ID = mt.MEETING_ID
;
Use Explicit Join Syntax and then setup your relationships using the ON conditions and the keys between the tables. Note I also used table aliases to shorten typying.
I have three tables in my Oracle db:
Peoples:
IdPerson PK
Name
Surname
Earnings:
IdEarning PK
IdPerson
EarningValue
Awards:
IdAward PK
IdPerson FK
AwardDescription
So one person can have many earnings, one earning or can have no any earnings. Also one person can have many awards, one award, or no any award.
I have to select Surname and AwardDescription but only for people who have any earnings, because it is possible to have some award but, also don't have any earning!
My problem is to make a correct group by statement. I use query posted below and I am selecting surname of person with a description of award, but it is duplicating for each row in Earnings for this person.
SELECT AwardDescription, Surname
FROM Awards
INNER JOIN People ON People.IdPerson= Awards.IdPerson
INNER JOIN Earnings ON Earnings .IdPerson= People.IdPerson;
How to group it and avoid duplicating rows for each earning of person?
One person can be in many rows, but with different awards.
You could add DISTINCT to your query:
SELECT DISTINCT AwardDescription, Surname
FROM Awards
INNER JOIN People ON People.IdPerson= Awards.IdPerson
INNER JOIN Earnings ON Earnings .IdPerson= People.IdPerson;
Or another option is to use EXISTS:
SELECT AwardDescription, Surname
FROM Awards
INNER JOIN People P ON P.IdPerson= Awards.IdPerson
WHERE EXISTS (
SELECT 1
FROM Earnings E
WHERE P.IdPerson = E.IdPerson);
Do a left outer join among the tables like
SELECT p.Surname, a.AwardDescription, e.EarningValue
FROM People p
LEFT JOIN Awards a ON p.IdPerson= a.IdPerson
LEFT JOIN Earnings e ON e.IdPerson= p.IdPerson
WHERE a.AwardDescription IS NOT NULL
OR e.EarningValue IS NOT NULL;