Multiply result rows in a query

Hi
How can i multiply the number of resulting rows in a query based on the value of a field.

For instance:
select customers.CustomerID, customers.CustomerName, customers.Address from Customers order by CustomerName
 
will give me a list of customers. Now, assuming i have a customers.Quantity field, i would like that each resulting row in the query will appear Quantity times, i.e if quantity=2, that customer's row will appear twice

Thanks
Jaime
LVL 2
GreatSolutionsC.I.OAsked:
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Ryan ChongCommented:
simply try:

select * from (
select customers.CustomerID, customers.CustomerName, customers.Address from Customers
union all
select customers.CustomerID, customers.CustomerName, customers.Address from Customers
where customers.quantity = 2
) a
 order by CustomerName
0
Pawan KumarDatabase ExpertCommented:
@Ryan -- if quantity = 3 then we have to again add another union all. This is not generic. :)
1
Olaf DoschkeSoftware DeveloperCommented:
You're not telling how you connect and query, let me assume PDO. then you could act this way:

$connect = new PDO($dsn, $user_name, $pass_word);

$sql = "Select * FROM Customers";	

$result = $connect->prepare($sql);

//bind parameter(s) to variable(s)
//$result->bindParam( . . . );

$status = $result->execute();

if (($status) && ($result->rowCount() > 0))
{
	$results = array();

	// fetch single rows multiplying with Customers.quantity
	while ($row = $result->fetch(PDO::FETCH_ASSOC))
	{
           for ($i=0; $i<$row['quantity']; $i++)
           {
		   $results[] = $row;
           }
	}

	//dump all data from associative array converted from query result
	var_dump($results);

}

$connect = null;

Open in new window


Bye, Olaf.
1

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GreatSolutionsC.I.OAuthor Commented:
Olaf!!
Great to see you active and more powerful than ever, know you since VFP days :-)
You are right, i didn't mention how i connect and query, it's done with Alpha Anywhere. While your solution cannot be adapted to my usecase ( i need to print a report based on the query result ), i can generate a recordset from the query and "scan" through it, then i'll just ask in the Alpha Anywhere forums how to base report on resulting array.
I will mark this as solution.

Thank you very much
Jaime
0
GreatSolutionsC.I.OAuthor Commented:
I posted my closing comment in the response to the thread
0
Olaf DoschkeSoftware DeveloperCommented:
Thanks,

so you're not using PHP. OK. I don't see a way (a simple way) to multiply rows by the value of a single column. In MSSQL I would perhaps cross apply a tally table on value<=Customers.Quantity or something like that, But the simpler idea is to do it on the client side anyway.

PHP will fetch into an array and you can multiply rows here, You also know VFP will have cursors and how you could act there. Whatever structure you have client side should be able to clone or repeat rows in that manner.

Bye, Olaf.
0
Ryan ChongCommented:
if quantity = 3 then we have to again add another union all. This is not generic. :)
@Pawan, well, this is true, all based on requirements.
1
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