How should I structure this code?

[DeepakJ]

Ok so I want to create an update in this table

 

productid invoicenum

xxx        yyy

xxy        yyz

 

But I want to change the productid from ""(initially entered before in teh script) to the actual key with this table.

There can be multiple invoice num in this table. How can I make a SQL instruction that will only update the FIRST "" string available. UPDATE productid SET productid='$productid' WHERE invoicenum=$invoicenum changes all the null strings at the particular invoice num.

 

Help would be greatly appreciated.

[deadimp]

What exactly are those fields? Is one of them your auto_increment?

As for only updating the first, you can use a LIMIT statement to confine your result to only one (or no) row. Ex:

$q="update `table` set `product_id`='$product_id' where `invoice_id`='$invoice_id' limit 0, 1";

I changed a couple of names there, just for the hell of it, also. Be sure that the variables you're putting in you MySQL query are formatted or restricted so that somebody can't make an injection attack against you.

[DeepakJ]

Its for internal use only, so no need.