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'
Related
S.no
emp_id
emp_name
Dept
1
100
John
Sales
2
100
John
Accounts
3
200
Mike
Sales
4
300
Mark
Sales
5
300
Mark
Accounts
6
400
Tom
Sales
I need to pull all the emp_id who are linked ONLY to Sales Dept and ignore the ones that are in both Sales and Accounts. I am using DB2 z/os. Any suggestions would be helpful? Thanks in advance.
An anti-join will produce the result you want.
For example:
select s.*
from employee s
left join employee a on a.emp_id = s.emp_id and a.dept = 'Accounts'
where s.dept = 'Sales' and a.emp_id is null
For good performance you can try adding the index:
create index ix1 on employee (emp_id, dept);
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 need to retrieve the name of those departments in which no students are enrolled.
Table: department
dept_id dept_name
1 IT
2 Electrical
3 Civil
4 Mechanical
5 Chemical
Table: stud_member
f_name dept_id age
AB 2 19
Rose 3 22
May 1 20
Noor 1 21
Haya 1 19
April 3 23
Sakina 2 20
For example the names of mechanical and chemical. I have written this query for it using outer join (explicitly maybe?) But is shows an error.
please tell me that why i cannot write:
SELECT dept_id, dept_name
FROM department
LEFT JOIN stud_member ON (WHERE NOT department.dept_id = stud_member.dept_id);
I will be grateful if anyone will tell me the correct answer!
Assuming dept_id in stud_member can not be NULL which is true when dept_id is a FOREIGN KEY
SELECT dept_id, dept_name
FROM department
WHERE dept_id NOT IN (SELECT dept_id FROM stud_member);
as suggested using NOT EXISTS does not have this problem
SELECT d.dept_id, d.dept_name
FROM department d
WHERE NOT EXISTS (SELECT * FROM stud_member s WHERE d.dept_id = s.dept_id);
You can select all departments where Right part of Left JOIN is NULL
SELECT d.dept_id, d.dept_name
FROM department d
LEFT JOIN stud_member sm ON d.dept_id = sm.dept_id
WHERE sm.dept_id IS NULL
does anyone know how to create a subquery to find all the employees under one manager? For example if I want to find someone that works on susan jones how would I create the query?
Manager Table:
Employee ID Manager_ID Name Title
1 NULL James Smith CEO
2 1 Ron Johnson Sales Manager
3 2 Fred Hobbs Sales Person
4 1 Susan Jones Support Manager
select employeename,managerid
from manager
where manager_id is not null
group by employeename ,manager_id
Well, supposing the table for employees is simply named Employee and its key is named 'Employee_ID' (like in the Manger table), then you just need to use a simple Join:
SELECT e.* FROM Employee AS e JOIN Manger AS m ON e.Employee_ID=m.Employee_ID WHERE m.Name='Susan Jones'
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)