How do I get a value from the previous row

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I want a value from a previous row.

myTable with values

RowNo Name Salary
1 Alan 20000
2 Alan 22000
3 Alan 24000

I want to get the previous value from the last row e.g. 22000

I do not have a row number in my table so done the following

select ROW_NUMBER() over (ORDER BY Name) AS RowNo,
* from myTable
where Name = 'Alan'

Any ideas with sample code would be fantastic

Posted 28-Jan-15 5:01am

Central_IT

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Tomas Takac 28-Jan-15 11:04am

Which database / version? SQL Server 2012 has nice windowing functions you can use.

Central_IT 28-Jan-15 11:07am

I am using SQL Server 2008 and the code will be part of a function

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CHill60 · Accepted Answer · 2015-01-28T06:09:00

This should do it

SQL

WITH CTE AS (
  SELECT
    rownum = ROW_NUMBER() OVER (ORDER BY Name, RowNo),
    Salary, RowNo, Name
  FROM myTable
)
SELECT
  cur.RowNo, cur.Name, cur.Salary, ISNULL(prev.Salary,0)
FROM CTE cur
LEFT OUTER JOIN CTE prev on prev.rownum = cur.rownum - 1

You said there was no row number in your table but your data showed a RowNo... it doesn't really matter but you might want to change the ORDER BY clause. Edit - just re-read your question - apologies about my confusion on RowNo - ignore me :-)

This produces the following results:

ROWNO NAME SALARY COLUMN_3
1     Alan 20000  0 
2     Alan 22000  20000 
3     Alan 24000  22000