Sql SELECT statement with paging vb.net

Question

I have looked at many other similar questions and cant get this to work for my statement. This is the SELECT statement that currently works, and I need to add paging.

      "SELECT TOP 15 * FROM  tblEvents WHERE (dbo.fnEventSearchDistance(@CityLat, " & _
      "@CityLong, latitude, longitude) <= @Radius AND (StartDate >= GETDATE())) "

This is the closest I have been able to get.

      "SELECT ROW_NUMBER() OVER(ORDER BY StartDate) AS RowNum, * FROM tblEvents " & _
      "WHERE RowNum BETWEEN ((@PageNum - 1) * @PageSize + 1) " & _
      "AND (@PageNum * @PageSize) " & _
      "ORDER BY StartDate"

      comm2.Parameters.AddWithValue("@PageSize", 25)
      comm2.Parameters.AddWithValue("@PageNum", 2)

I need a SELECT Statement that rewrites the first SELECT statement to incorporate paging, where I can add pageSize and pageNum parameters

Answer 1

Assuming SQL Server 2008 and previous, you should try this:

"SELECT col1, col2 FROM (SELECT ROW_NUMBER() OVER(ORDER BY StartDate) AS RowNum, * FROM tblEvents) AS E " & _
"WHERE RowNum BETWEEN ((@PageNum - 1) * @PageSize + 1) " & _
"AND (@PageNum * @PageSize) " & _
"ORDER BY StartDate"

Note that I put col1, col2 on the select, you should put the columns you need there. For SQL Server 2012, this is quite simpler:

"SELECT * FROM tblEvents ORDER BY StartDate " & _ 
"OFFSET (@PageNum - 1) * @PageSize ROWS FETCH NEXT @PageNum ROWS ONLY"

Answer 2

CREATE  PROCEDURE [dbo].[usp_PageResults_NAI] 
(
    @startRowIndex int,
    @maximumRows int
)
AS

DECLARE @first_id int, @startRow int

-- A check can be added to make sure @startRowIndex isn't > count(1)
-- from employees before doing any actual work unless it is guaranteed
-- the caller won't do that

-- Get the first employeeID for our page of records
SET ROWCOUNT @startRowIndex
SELECT @first_id = employeeID FROM employees ORDER BY employeeid

-- Now, set the row count to MaximumRows and get
-- all records >= @first_id
SET ROWCOUNT @maximumRows

SELECT e.*, d.name as DepartmentName 
FROM employees e
   INNER JOIN Departments D ON
       e.DepartmentID = d.DepartmentID
WHERE employeeid >= @first_id
ORDER BY e.EmployeeID

SET ROWCOUNT 0

GO 

Answer 3

Try this instead:

;With ranked AS
(
   SELECT ROW_NUMBER() OVER(ORDER BY StartDate) AS RowNum,  * 
   FROM tblEvents
)
SELECT * FROM Ranked
WHERE RowNum BETWEEN ((@PageNum - 1) * @PageSize + 1)
    AND (@PageNum * @PageSize)
    ORDER BY StartDate

Answer 4

You cannot reference ROW_NUMBER in the WHERE clause, using a Common Table Expression (CTE) can help with paging.

WITH Paging AS
(
   SELECT ROW_NUMBER() OVER (ORDER BY StartDate) AS RowNum
    , *
   FROM tblEvents
)
SELECT *
FROM Paging AS p
WHERE p.RowNum BETWEEN ((@PageNum - 1) * @PageSize + 1)
   AND (@PageNum * @PageSize)
ORDER BY p.StartDate ASC;

Starting in SQL 2012, you will have access to OFFSET FETCH in your ORDER BY to help making paging easier, and more efficient.