Returning row number on MS Access
I have 4 tables, from开发者_开发问答 which i select data with help of joins in select query...I want a serial no.(row number) per record as they are fetched. first fetched record should be 1, next 2 and so on...
In oracle the equiavelent in RowNum.
The answer by Brettski is ASP flavored and would need a lot of editing.
SELECT DCOUNT("YourField","YourTable","YourField <= '" & [counter] & "'")
AS RowNumber,
YourField as counter FROM YourTable;
Above is your basic syntax. You are likely to find this runs very slow. My typical solution is a bucket table with Autonumber field. That seems kludgy, but it gives me control and probably in this case it allows speed.
Using a sorted Make Table Query in Access, I use the following (wouldn't work if you look at the Query, as that would increment the number when you don't want it to)....
setRowNumber 'resetting increment before running SQL
DoCmd.RunSQL ... , rowNumber([Any Field]) AS ROW, ...
'Increment Number: Used to create temporary sorted Table for export
Private ROWNUM As Long
'dummyField: must take an input to update in Query
Public Function rowNumber(ByVal dummyField As Variant, Optional ByVal incBy As Integer = 1) As Long
ROWNUM = ROWNUM + incBy 'increments before value is returned
rowNumber = ROWNUM
End Function
Public Function setRowNumber(Optional ByVal setTo As Long = 0) As Long
ROWNUM = setTo
setRowNumber = ROWNUM
End Function
With the following table
SET NOCOUNT ON
CREATE TABLE people
(
firstName VARCHAR(32),
lastName VARCHAR(32)
)
GO
INSERT people VALUES('Aaron', 'Bertrand')
INSERT people VALUES('Andy', 'Roddick')
INSERT people VALUES('Steve', 'Yzerman')
INSERT people VALUES('Steve', 'Vai')
INSERT people VALUES('Joe', 'Schmoe')
You can use a sub query to create the counting row:
SELECT
rank = COUNT(*),
a.firstName,
a.lastName
FROM
people a
INNER JOIN people b
ON
a.lastname > b.lastname
OR
(
a.lastName = b.lastName
AND
a.firstName >= b.firstName
)
GROUP BY
a.firstName,
a.lastName
ORDER BY
rank
The problem with this method is that the count will be off if there are duplicates in your results set.
This article explains pretty well how to add a row counting column to your query.
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