I have the below query with multi joins you can find it on sql fiddle thats giving me invalid DEF.ID
How can I make the below join to read from DEFINITION table
SELECT *
FROM DEFINITION DEF
WHERE EXISTS (SELECT 1
FROM EMPLOYEE E
INNER JOIN MONTHLY_PAYMENT MP ON (MP.ID = E.CODE)
INNER JOIN DEPARTMENT DEP ON (DEP.ID = DEF.ID)
)
By Oracles rules, there are two problems, first DEPARTMENT needs to be related to at least one of the the two tables it is being joined to. And second, DEF cannot be used as a nested inner condition join and so must be used in the WHERE clause instead.
SELECT DEF.ID
FROM DEFINITION DEF
WHERE EXISTS
(
SELECT 1 FROM EMPLOYEE E
INNER JOIN MONTHLY_PAYMENT MP ON (MP.ID=E.CODE)
INNER JOIN DEPARTMENT DEP ON DEP.ID=E.DEP_ID
WHERE DEP.ID=DEF.ID
)
Related
I am trying to get all the values from the first left table but when I use two left joins its restricting the values from first table.
I used the below query
SELECT P.person_id, TS.Task_Id, TS.skill
FROM Person P
LEFT JOIN Person_Skill PS ON P.person_id = PS.person_id
LEFT JOIN Task_Skill TS ON PS.Skill = TS.Skill
WHERE ts.task_id = 245
I need all the person id from person table.
Just move the condition on the left joined table from the where clause to the on clause of the join:
select p.person_id, ts.task_id, ts.skill
from person p
left join person_skill ps
on p.person_id = ps.person_id
left join task_skill ts
on ps.skill = ts.skill
and ts.task_id = 245 --> here
Rationale: conditions in the where clause are mandatory. If there is no match in ts, then condition ts.task_id = 245 cannot be satisfied, since ts.task_id is null.
Use the filter condition in a sub query instead of using it as a global filter outside. This should give you the output that you desire.
SELECT P.person_id,TS.Task_Id,TS.skill FROM Person P
LEFT JOIN Person_Skill PS
ON P.person_id=PS.person_id
LEFT JOIN
(Select * from Task_Skill where task_id = 245) TS
ON PS.Skill=TS.Skill;
I have a table AMZ_EMPLOYEE_DETAILS with Employee Id, Employee Name and Supervisor1 and Supervisor 2. The Supervisors are employee itself but represented by their name.
My task was to replace the Supervisor names with their Ids.
I have used the following query to obtain the solution but it uses sub-queries and the query does look optimized. For this I have also made a dimension table with all the Id and Employee Names ,table AMZ_EMPLOYEE
SELECT S1.ID, S1.EMP_NAME, S1.SUPER_1_NEW, ZZ.ID AS SUPER_2_NEW
FROM
(SELECT A.ID,A.EMP_NAME,A.SUPER_1,A.SUPER_2,Z.ID AS SUPER_1_NEW
FROM AMZ_EMPLOYEE_DETAILS A
LEFT JOIN
AMZ_EMPLOYEE Z
ON A.SUPER_1 = Z.EMP_NAME ) S1
LEFT JOIN
AMZ_EMPLOYEE ZZ
ON S1.SUPER_2 = ZZ.EMP_NAME
ORDER BY 1
The following is the expected output.
The logic to use two self-LEFT JOIN is correct. You don't need to use subqueries though. Consider:
SELECT a.id, a.emp_name, a1.id, a2.id
FROM amz_employee_details a
LEFT JOIN amz_employee a1 ON a1.emp_name = a.super_1
LEFT JOIN amz_employee a2 ON a2.emp_name = a.super_2
I want to join two tables and then I want to join this result with another table
but it doesn't work
select * from
(
(select SeId,FLName,Company from Sellers) s
inner join
(select SeId,BIId from BuyInvoices) b
on s.SeId=b.SeId
) Y
inner join
(select * from BuyPayments) X
on Y.BIId=X.BIId
thanks
In most databases, your syntax isn't going to work. Although parentheses are allowed in the FROM clause, they don't get their own table aliases.
You can simplify the JOIN. This is a simpler way to write the logic:
select s.SeId, s.FLName, s.Company, bp.*
from Sellers s inner join
BuyInvoices b
on s.SeId = b.SeId inner join
BuyPayments bp
on bp.BIId = b.BIId;
Having trouble with joins.
I have a table called subjects
subno subname
30006 Math
31445 Science
31567 Business
I also have a another table called enrollment
subno sno
30009 980008
4134 988880
etc..
how to list subject numbers and subject names for student 9800007 ?
If you want to return zero rows for students without an enrolment, use a LEFT [OUTER] JOIN, eg:
SELECT e.sno, s.subno, s.subname
FROM enrollment e LEFT OUTER JOIN subjects s ON s.subno = e.subno
WHERE e.sno=988880;
To return no rows for students without enrolments, use an INNER JOIN:
SELECT e.sno, s.subno, s.subname
FROM enrollment e INNER JOIN subjects s ON s.subno = e.subno
WHERE e.sno=988880;
Note that join order is important for outer joins (RIGHT [OUTER] JOIN and LEFT [OUTER] JOIN - the OUTER keyword is optional) but not for INNER JOIN. For that reason, #swetha's answer has a problem: the join order is reversed if you're looking for information about a student.
See this SQLFiddle
Try this
select *
from subjects s
left join enrollment e on s.subno = e.subno
where sno=9800007
I'm trying to join multiple tables together for building a report. The report lists a course, revisions made to it, and who requested, made and approved the revisions.
Under requested, made an approved, the values are employee numbers. I'm trying to join my innerjoined table above, with the Employee table so I can list the names (not just employee numbers) of those that requested, made and approved revisions.
This is what I have which I know is totally wrong.
SELECT *
FROM Courses
INNER JOIN CourseRevisions ON CourseRevisions.PELID = Courses.PELID
INNER JOIN CourseGroups ON CourseGroups.CourseGroupID = Courses.CourseGroupID
INNER JOIN [dbo].[OPG_Employees] ON OPG_Employees.EmployeeID = CourseRevisions.UpdatedBy
AND OPG_Employees.EmployeeID = CourseRevisions.ApprovedBy
AND OPG_Employees.EmployeeID = CourseRevisions.RequestedBy
This only returns a single result which just happens to have the same employee ID listed for all 3 (Requested, Approved and Updated)
How would i get it so I can get the table result for individual employees in each?
You have to join to the OPG_Employees table once for each field, i.e. 3 times in the example above. One INNER JOIN to it for UpdatedBy, one INNER JOIN for ApprovedBy, one INNER JOIN for RequestedBy.
Something like so:
SELECT *
FROM Courses
INNER JOIN CourseRevisions ON CourseRevisions.PELID = Courses.PELID
INNER JOIN CourseGroups ON CourseGroups.CourseGroupID = Courses.CourseGroupID
INNER JOIN [dbo].[OPG_Employees] empUpdatedBy ON empUpdatedBy.EmployeeID = CourseRevisions.UpdatedBy
INNER JOIN [dbo].[OPG_Employees] empApprovedBy ON empApprovedBy.EmployeeID = CourseRevisions.ApprovedBy
INNER JOIN [dbo].[OPG_Employees] empRequestedBy ON empRequestedBy.EmployeeID = CourseRevisions.RequestedBy
You need a separate join for each employee being referenced:
SELECT *
FROM Courses INNER JOIN
CourseRevisions
ON CourseRevisions.PELID = Courses.PELID INNER JOIN
CourseGroups
ON CourseGroups.CourseGroupID = Courses.CourseGroupID INNER JOIN
[dbo].[OPG_Employees] UpdateEmp
ON UpdateEmp.EmployeeID = CourseRevisions.UpdatedBy INNER JOIN
[dbo].[OPG_Employees] ApprovedEmp
on OPG_ApprovedEmp.EmployeeID = CourseRevisions.ApprovedBy INNER JOIN
[dbo].[OPG_Employees] RequestedEmp
on RequestedEmp.EmployeeID = CourseRevisions.RequestedBy
Your original formulation required that all three ids be exactly the same.