I am trying to run following SQL query on northwind database :
SELECT * FROM (
SELECT DISTINCT ROW_NUMBER() OVER (ORDER BY Joinning DESC) rownum,
LastName, Country, HireDate AS Joinning
FROM Employees
WHERE Region IS NOT NULL
) r
It's giving me the error :
Invalid column name 'Joinning'.
The 'rownumber' is required for pagination.
Can anybody please suggest how I can sort on the Joining alias with the rownumber generated ?
--A possible work around
Just figured out a work around; please suggest if anything is wrong or need changes :
SELECT ROW_NUMBER() OVER (ORDER BY Joinning DESC) rownum,* FROM (
SELECT
LastName, Country, HireDate AS Joinning
FROM Employees
WHERE Region IS NOT NULL
) r
--To put further where clause on row number(what I wanted to do for pagination):
With myres as(
SELECT ROW_NUMBER() OVER (ORDER BY Joinning DESC) rownum,* FROM (
SELECT
LastName, Country, HireDate AS Joinning
FROM Employees
WHERE Region IS NOT NULL
) a
) Select * from myres where myres.rownum > 0 and myres.rownum < = 0+20
Try
SELECT * FROM (
SELECT DISTINCT ROW_NUMBER() OVER (ORDER BY HireDate DESC) rownum,
LastName, Country, HireDate AS Joinning
FROM Employees
WHERE Region IS NOT NULL
) r
Hope you ahve joinning in your table.
The order by clause is usually given at the last of the query like this :
SELECT * FROM (
SELECT DISTINCT ROW_NUMBER() rownum,
LastName, Country, HireDate AS Joinning)
FROM Employees
WHERE Region IS NOT NULL ORDER BY Joinning DESC)
Hope this helps you!
Use Original Name of the field, That will work just fine HireDate
SELECT * FROM (
SELECT DISTINCT ROW_NUMBER() OVER (ORDER BY HireDate DESC) rownum,
LastName, Country, HireDate AS Joinning
FROM Employees
WHERE Region IS NOT NULL
) r
Related
I want one employee from every department (EmpDepartment), for example in my table there are:
3 employees with EmpDepartment 1
2 employees with EmpDepartment 2 and
1 Employee with EmpDepartment 3
I want EmployeeId, EmployeeName and EmpDepartment of any one employee from each separate department.
Use a windowing function like this:
SELECT *
FROM (
SELECT
E.*,
ROW_NUMBER() OVER (PARTITION BY EmpDepartment) AS RN
FROM Employee
) X
WHERE X.RN = 1
You can add an order clause the the windowing function if you have a business rule that you want to use in picking the employee
eg
ROW_NUMBER() OVER (PARTITION BY EmpDepartment order by EmployeeId) AS RN
This will get a random employee from each department due to ordering by NEWID()...
SELECT * FROM
(
SELECT EmployeeID, EmployeeName, EmployeeEmail
, ROW_NUMBER() OVER (PARTITION BY EmpDepartment ORDER BY NEWID()) AS rn
FROM dbo.Employee
) x
WHERE x.rn = 1
You can change the order by clause to something else if you want to.
This will return the employee from each department having the minimum EmployeeID in that department (since it is not important which employee will be in the results):
SELECT e.* FROM Employee e
WHERE NOT EXISTS (
SELECT 1 FROM Employee
WHERE EmpDepartment = e.EmpDepartment AND EmployeeID < e.EmployeeID
)
SELECT Top(1) EmployeeID, EmployeeName, EMPDeptartment FROM Employee WHERE EmpDetpartment = 1
UNION
SELECT Top(1) EmployeeID, EmployeeName, EMPDeptartment FROM Employee WHERE EmpDetpartment = 2
UNION
SELECT Top(1) EmployeeID, EmployeeName, EMPDeptartment FROM Employee WHERE EmpDetpartment = 3
You can either use rownumber to find any employee of a particular dept change rn to any value as 1,2,...etc
Select department, employee
from (
Select department, employee,
row_number() over (partition by department order by employee) rn
)
where rn =1;
or use simple group by
Select department, max(employee)
from table
group by department
so i have 3 tables linked together named office, employee, and dependent.
office: Oid (PK), officeName
employee: EID(PK), Fname, Lname, JobTitle, Salary, DOH, Gender, DOB, OID(FK1), Supervisor(FK2)
Dependent: DID(PK), Fname, Lname, Gender, EID(FK1)
Here is the link to the picture of the tables:
http://classweb2.mccombs.utexas.edu/mis325/class/hw/hw12a.jpg
I need to display concatenated name and EID of 5 employees with the largest number of dependents, if there is a tie for the five largest, then I need to display all of the tying employees.
I am confused on how to begin. please help :)
thank you in advance
Just break down the problem:
How many dependents an EID has:
SELECT EID, COUNT(*) AS C
FROM Dependent
GROUP BY EID
Add a rank
SELECT EID, C, RANK() OVER (ORDER BY C DESC)
FROM (
SELECT EID, COUNT(*) AS C
FROM Dependent
GROUP BY EID
) S
We want the first 5
SELECT EID
FROM (
SELECT EID, C, RANK() OVER (ORDER BY C DESC) AS R
FROM (
SELECT EID, COUNT(*) AS C
FROM Dependent
GROUP BY EID
) S
) S2
WHERE R <= 5
Now ask for what you want:
SELECT * -- or whatever
FROM Employee
WHERE EID IN (
SELECT EID
FROM (
SELECT EID, C, RANK() OVER (ORDER BY C DESC) AS R
FROM (
SELECT EID, COUNT(*) AS C
FROM Dependent
GROUP BY EID
) S
) S2
WHERE R <=5
) S3
I suggest you run each step and make sure it gives you the expected results.
Ummm I would try something like this:
Select TOP 5
a.FNAME,
a.LNAME,
a.EID,
Count(b.EID) as Dependents
FROM employee a
LEFT JOIN dependent b on a.EID = b.EID
group by 1,2,3 order by Dependents desc
with a as (
select a.*, row_number() over (partition by department order by attributeID) rn
from attributes a),
e as (
select employeeId, department, attribute1, 1 rn from employees union all
select employeeId, department, attribute2, 2 rn from employees union all
select employeeId, department, attribute3, 3 rn from employees
)
select e.employeeId, a.attributeid, e.department, a.attribute, a.meaning,
e.attribute1 as value
from e join a on a.department=e.department and a.rn=e.rn
order by e.employeeId, a.attributeid
this query is written by Ponder Stibbons for the answer of this question. But i am too dizzy with it as i quite don't understand what is going on here. i am new to SQL . so i would appreciate if anyone can explain what is happening on this query . thank you
Basically he unpivots the data using 3 select statements (1 for each attribute) and UNION them together to make a common table expression so that he gets rows for each employees attribute.
select employeeId, department, attribute1, 1 rn from employees union all
select employeeId, department, attribute2, 2 rn from employees union all
select employeeId, department, attribute3, 3 rn from employees
The other table he using a window function to assign a number to attribute, department. He uses this number later to join back to his unpivoted data. He posted his code for the example.
select a.*, row_number() over (partition by department order by attributeID) rn
from attributes a
I would suggest you use his example data he provided and run the following. This will show you the CTEs. I think once you see that data it will make more sense.
with a as (
select a.*, row_number() over (partition by department order by attributeID) rn
from attributes a),
e as (
select employeeId, department, attribute1, 1 rn from employees union all
select employeeId, department, attribute2, 2 rn from employees union all
select employeeId, department, attribute3, 3 rn from employees
)
SELECT * from a
SELECT * from e
I have a table employee
id name dept
1 bucky shp
2 name shp
3 other mrk
How can i get the name of the department(s) having maximum number of employees ? ..
I need result
dept
--------
shp
SELECT cnt,deptno FROM (
SELECT rank() OVER (ORDER BY cnt desc) AS rnk,cnt,deptno from
(SELECT COUNT(*) cnt, DEPTNO FROM EMP
GROUP BY deptno))
WHERE rnk = 1;
Assuming you are using SQL Server and each record representing an employee. So you can use window function to get the result
WITH C AS (
SELECT RANK() OVER (ORDER BY dept) Rnk
,name
,dept
FROM table
)
SELECT TOP 1 dept FROM
(SELECT COUNT(Rnk) cnt, dept FROM C GROUP BY dept) t
ORDER BY cnt DESC
With common table expressions, count the number of rows per department, then find the biggest count, then use that to select the biggest department.
WITH depts(dept, size) AS (
SELECT dept, COUNT(*) FROM employee GROUP BY dept
), biggest(size) AS (
SELECT MAX(size) FROM depts
)
SELECT dept FROM depts, biggest WHERE depts.size = biggest.size
Based on one of the answer, Let me try to explain step by step
First of all we need to get the employee count department wise. So the firstly innermost query will run
select count(*) cnt, deptno from scott.emp group by deptno
This will give result as
Now out of this we have to get the one which is having max. employee i.e. department 30.
Also please note there are chances that 2 departments have same number of employees
The second level of query is
select rank() over (order by cnt desc) as rnk,cnt,deptno from
(
select count(*) cnt, deptno from scott.emp group by deptno
)
Now we have assigned ranking to each department
Now to select rank 1 out of it. we have a simplest outer query
select * from
(
select rank() over (order by cnt desc) as rnk,cnt,deptno from
(
select count(*) cnt, deptno from scott.emp group by deptno
)
)
where rnk=1
So we have the final result where we got the department which has the maximum employees. If we want the minimum one we have to include the department table as there are chances there is a department which has no employees which will not get listed in this table
You can ignore the scott in scott.emp as that is the table owner.
The above SQL can be practised at Practise SQL online
I have an Employee Table with their DeptCode. I want list of distinct DeptCode and their first created date in the Employee Table. This will also tell which employee was first entered for a specific dept in the Employee Table.
I used:
SELECT DISTINCT DEPTCODE,
CREATEDDATE
FROM EMPLOYEE
The Date Return is incorrect.
Any specific syntax to handle this issue.
Try:
SELECT DEPTCODE,
Min(CREATEDDATE)
FROM EMPLOYEE
GROUP BY DEPTCODE
If you want the department codes, earliest creation date, and the name of the employee, then I would recommend window functions:
select deptcode, name, createddate
from (select e.*,
row_number() over (partition by deptcode order by createddate) as seqnum
from employee e
) e
where seqnum = 1;
You can use GROUP BY and MIN to achieve this.
SELECT DEPTCODE, MIN(CREATEDDATE)
from EMPLOYEE
GROUP BY DEPTCODE
Something like this.
SELECT deptcode,
employee_name,
minddate
FROM employee
JOIN (SELECT deptcode,
Min(createddate) mindate
FROM employee
GROUP BY deptcode) temp
ON employee.deptcode = temp.deptcode
AND createddate = mindate