I'm working on the adventureworks example database.
I have a table with employee's, which all have a certain manager. So in the table employee's there is a column ManagerID.
Also in the table employee there's a ContactID, which contains the name of that employee.
I would like to have a list with all the managers and their names. How can I pull this off?
The table looks something like
EmployeeID ContactID ManagerID
---------- --------- ---------
1 21 4
2 24 4
3 32 7
4 34 2
5 35 2
6 42 7
7 44 4
So i'll need a DISTINCT list of the managerID, and then search for each managerID their appropreate ContactID.
So:
manager of employee 1 is Employee 4 with the ContactID 34.
manager of employee 3 is Employee 7 with the ContactID 44.
manager of employee 4 is Employee 2 with the ContactID 24.
Thanks.
You can do it joining the table myTable with itself matching manager_id's with employee_id's
select
t.employeeid as employee_id,
t.manager_id as manager_id,
t2.contact_id as manager_contact_id
from mytable t left outer join mytable t2 on t.managerid = t2.employeeid
SELECT ManagerID, EmployeeID, ConactID
FROM ´yourtable´
GROUP BY ManagerID
There you get the grouped data.
If you want to have Managers listed as well you have to JOIN the data again (self-join)
Related
Given the following Table (In Postgres):
EmployeeID
EmployeeName
ManagerID
1
David
NULL
2
Jessica
NULL
3
Gregg
1
4
Joe
3
5
Brandon
NULL
6
Leslie
4
7
Harry
6
8
Paul
NULL
9
Frank
5
Starting from Employee ID 7 (Harry) - how do I list only the records, bottom-up, in the hierarchy until I get to the ultimate manager (which should be David, in this case)? Should I use recursive CTE? If so, how does that query look?
Expected Output:
EmployeeID
EmployeeName
ManagerID
1
David
NULL
3
Gregg
1
4
Joe
3
6
Leslie
4
7
Harry
6
In the common table expression, you can recognize:
the base step, where you select the record relatively to employee no 7
the recursive step, where you match managers with currently retrieved employees.
The recursion stops when the INNER JOIN does not return any more extra record.
WITH RECURSIVE cte AS (
SELECT * FROM tab WHERE EmployeeID = 7
UNION ALL
SELECT mgr.*
FROM cte emp
INNER JOIN tab mgr
ON emp.ManagerID = mgr.EmployeeID
)
SELECT *
FROM cte
Check the demo here.
I have the below tables:
Corporate table:
CorporateId DirectorId ManagerId SalesId
1 1 1 1
2 2 2 3
3 3 4 5
Employee table:
EmployeeId FirstName LastName
1 Tim Sarah
2 Tom Paulsen
3 Tam Margo
4 Eli Lot
5 Ziva Lit
I want to display, for one corporate,the names of the Director, Manager and Sales in rows. Example with corporate 3:
EmployeeId FirstName LastName
3 Tam Margo
4 Eli Lot
5 Ziva Lit
How can I do that? I know how to display rows as columns using pivot, but unsure if pivot can be used here also.
Any help please?
You may join the two tables as the following:
SELECT E.EmployeeId, E.FirstName, E.LastName
FROM Employee E JOIN Corporate C
ON E.EmployeeID IN (C.DirectorId ,C.ManagerId ,C.SalesId)
WHERE C.CorporateId=3
See a demo.
You can first un-pivot your rows into columns by using cross apply, after which you simply join the pivoted rows to your employee table:
select e.*
from corporate c
cross apply (
select EmployeeId from (
values (Directorid), (ManagerId), (SalesId)
)r(EmployeeId)
)r
join employee e on e.EmployeeId = r.EmployeeId
where c.CorporateId = 3;
Here are the details of the tables:
Employee :
emp_ID | Primary Key
emp_name | Varchar
emp_email | varchar <br>
emp_dept_id | Foreign Key
Departments :
dept_ID | Primary Key
dept_name | Varchar
emp_id | Foreign Key
Manager details are already there in the employee table.
I am using Oracle Database.
Employee:
emp_ID emp_name emp_email emp_dept_id
1 Cyrus abc#xyz.com 10
2 Andrew xyz#abc.com 20
3 Mark xyz#abc.com 10
4 Tony xyz#abc.com 10
5 Elvis xyz#abc.com 20
6 Rock xyz#abc.com 10
7 George xyz#abc.com 20
8 Mary xyz#abc.com 10
9 Thomas xyz#abc.com 20
10 Martin xyz#abc.com 10
Depqartments:
dept_id dept_name emp_id
10 Accounts 4
20 Development 9
These are the data in the tables. In Department table, emp_id(Foreign key) indicates the head/manager of the department .
You can try following query:
SELECT
D.DEPT_ID,
D.DEPT_NAME,
D.EMP_ID AS MANAGER_ID,
E.EMP_NAME AS MANAGER_NAME,
E.EMP_EMAIL AS MANAGER_EMAIL,
E.CNT AS "number of employees"
FROM
DEPARTMENT D
JOIN (
SELECT
EMP_ID,
EMP_NAME,
EMP_EMAIL,
EMP_DEPT_ID,
COUNT(1) OVER(
PARTITION BY EMP_DEPT_ID
) AS CNT
FROM
EMPLOYEE
) E ON ( E.DEPT_ID = D.EMP_DEPT_ID
AND E.EMP_ID = D.EMP_ID );
Cheers!!
This is pretty straightforward. You want to get the department details (1) and also include the employees associated with that department (2).
Get the department details:
SELECT <dept_col1>, <dept_col2>, ...
FROM Department
Get a summary of employees per department:
SELECT dept_ID, <aggregation> AS MyAgg
FROM department
GROUP BY dept_ID
Here you replace <aggregation> with whatever you're trying to find. In your case it would be COUNT(*).
Combine the two results. You want to join the data from (2) to (1). How are these two tables related? Here you write a LEFT JOIN to connect them on the PK/FK relationship:
SELECT
dept.<col1>, dept.<col2>, ...,
COALESCE(emp.MyAgg,0) AS MyAgg
FROM Department dept
LEFT JOIN (
SELECT dept_ID, <aggregation> AS MyAgg
FROM department
GROUP BY dept_ID
) emp ON dept.<FK> = emp.<PK>
Get the department manager's info by adding another LEFT JOIN:
SELECT
dept.<col1>, dept.<col2>, ...,
mgr.<col1>,
COALESCE(emp.MyAgg,0) AS MyAgg -- In case there are 0 employees
FROM Department dept
LEFT JOIN employee mgr ON dept.<FK> = mgr.<PK>
LEFT JOIN (
SELECT dept_ID, <aggregation> AS MyAgg
FROM department
GROUP BY dept_ID
) emp ON dept.<FK> = emp.<PK>
Give it a try and see how far you get. If you get stuck let me know.
I have a database:
Staff Name
1 Blake
2 Jake
Mgr Emp
2 6
2 8
3 5
4 7
Is it possible to search up all employees but list them under the manager?
Select all:
Staff Name Mgr
1 Blake null
2 Jake null
6 Scott 2
8 Jack 2
3 Clark null
5 Martin 3
4 Smith null
7 Scott 4
And is there a way to look up the team when a staff is searched?
Search: "Scott"
Returns:
Staff Name Mgr
2 Jake null
6 Scott 2
8 Jack 2
http://rextester.com/OAREI7219 is solution
CREATE TABLE Managers (
MgrID int ,
EmpID int
)
CREATE TABLE Staff (
EmpID int,
name nvarchar(50)
)
Query is ;
SELECT
s.EmpID AS Staff,
s.name AS Name,
m.MgrID
FROM Staff s LEFT JOIN Managers m ON s.EmpID = m.EmpID ;
GO
Assuming that you have:
a table "staff" with all the people in the company. For clarity I will rename the "Staff" column to "id".
a many to many table "staff_manager" to link employees with their managers. For clarity I will rename the "Mgr" column to "manager_id" and the "Emp" to "employee_id".
all tables named lowercase and plural.
You may do:
SELECT employees.id, employees.name, managers.id, managers.name
FROM staff as employees
LEFT JOIN employee_managers ON (employee_managers.employee_id = employees.id)
LEFT JOIN staff as managers ON (managers.id = employee_managers.manager_id)
for the second query you add a where clause to the above query:
WHERE managers.name = "Scott" OR employees.name = "Scott"
NOTE: If you may change the model of your database, I would suggest to
set a UNIQUE constrain on the employee_id of the staff_managers table,
so that one employee can have ONLY ONE manager.
To get All Employees with their managers. Try
Select staff.Id,Staff.name,managers.mgr
From staff left join managers on staf.id=managers.emp
To search about employee and get his team with the manager also. Try
— Search: 'scott'
Select staff.Id,Staff.name,managers.mgr
From staff left join managers on staf.id=managers.emp
Where managers.mgr =(select t.mgr from managers as t where t.emp='scott')
Union all
Select staff.Id,Staff.name,managers.mgr
From managers left join staff on staf.id=managers.mgr
Where managers.emp='scott'
I have a requirement in such a way that it should join two tables with more than 100k records in one table and just 5 records in another table as shown below
Employee Dept Result
id Name deptid deptid Name Name deptid Name
1 Jane 1 1 Science Jane 1 Science
2 Jack 2 2 Maths Dane 1 Science
3 Dane 1 3 Biology Jack 2 Maths
4 Drack 3 4 Social Drack 3 Biology
5 Drim 5 Zoology Kery 4 Social
6 Drum 5 Drum 5 Zoology
7 Krack
8 Kery 4
.
.
100k
Which join need to be used to get the query in an better way to perform to get the result as shown.
I just want the query to join with other table from employee table only which has dept which i thought of below query but wanted to know is there any better way to do it.
Select e.name,d.deptid,d.Name from
(Select deptid,Name from Employee where deptid IS NOT NULL) A
and dept d where A.deptid=d.deptid;
Firstly not sure why you are performing your query the way you are. Should be more like
SELECT A.name, D.deptid,D.Name
FROM Employee A
INNER JOIN dept D
ON A.deptid = D.deptid
No need of the IS NOT NULL statement.
If this is a ONE TIME or OCCASIONAL thing and performance is key (not a permanent query in your DB) you can leave out the join altogether and do it using CASE:
SELECT
A.name, A.deptid,
CASE
WHEN A.deptid = 1 THEN "Science"
WHEN A.deptid = 2 THEN "Maths"
...[etc for the other 3 departments]...
END as Name
FROM Employee A
If this is to be permanent and performance is key, simply try applying an INDEX on the foreign key deptid in the Employee table and use my first query above.