How to get NULL as value when select top (n) records return less record

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Hello everyone,

I have one query which is : select top 5 Salary from FEmployee E where E.Designation ='Manager'

this query returns me 4 records as there are only 4 records which match the criteria.

Now what i want is when it returns 4 records and i select top 5 records then it should return me 5th record as NULL

Please help me in achieving this. I am really stuck up.

Thanks.

Krunal

Posted 3-Sep-14 20:15pm

krunalpanchalN

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[no name] 4-Sep-14 2:27am

why it's necessary like this?
If you want to add blank row then add it front end in your dataTable

Thanks7872 4-Sep-14 2:28am

What you mean by this line : when it returns 4 records and i select top 5 records then it should return me 5th record as NULL?

2 solutions

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_Maxxx_ · Answer 1 · 2014-09-03T21:08:00

Solution 1

Something like

SQL

Select top 5 salary from
(
select top 5  salary from Employee where designation = 'Manager'
union all
select null from employee

) AS ABC

should do what you want it to.

Posted 3-Sep-14 21:08pm

_Maxxx_

Updated 3-Sep-14 21:16pm

v2

Comments

Gihan Liyanage 4-Sep-14 3:19am

GREAT SOLUTION Max !,I have edited bit by adding alias, because otherwise it might had syntax error in query,

_Maxxx_ 4-Sep-14 6:15am

Thanks - I think I missed that when I copied it over from SSMS - it was 5-past going-home time so I was i a rush :)

Gihan Liyanage 4-Sep-14 6:18am

Ohh , yes I thought it was a mistake..

_Asif_ · Answer 2 · 2014-09-03T21:38:00

Solution 2

A more elegant solution could be like

SQL

DECLARE @TBL TABLE
(
	EMPID INT,
	DESIGNATION VARCHAR(20),
	SALARY FLOAT
)

INSERT INTO @TBL (EMPID, DESIGNATION, SALARY)
SELECT 102, 'MANAGER', 55000
UNION ALL
SELECT 234, 'MANAGER', 45000
UNION ALL
SELECT 345, 'MANAGER', 35000
UNION ALL
SELECT 446, 'MANAGER', 25000

SELECT T.SALARY
FROM 
	(select 1 as ROWID
	UNION ALL
	select 2
	UNION ALL
	select 3 
	UNION ALL
	select 4 
	UNION ALL
	select 5 
	) A LEFT OUTER JOIN 
	(
	SELECT TOP 5 ROW_NUMBER() OVER (ORDER BY EMPID) AS ROWID, *
	FROM @TBL T
	) T ON T.ROWID = A.ROWID

Posted 3-Sep-14 21:38pm

_Asif_

Comments

_Maxxx_ 4-Sep-14 6:21am

wow - not sure about elegant, but certainly more complex! Surely, if you decided you wanted 50 rows instead of 5, this is going to prove a little harder to maintain?

_Asif_ 4-Sep-14 7:39am

Well it could manage additional NULL rows if Top 5 returns < 4 rows as well and that's the reason for being elegant :) Well the interim table was used just to explain the concept, a more appropriate solution could be to use a proper table instead of interim table for the same purpose.