So, like you suggested, there are basically 3 choices : 1- for each item, either write your different invoice numbers in different invoice fields, 2- or all in the same invoice field, 3- or... the "parent" way, which could work well.
Multiple (
number) fields
might probably a good way to sort (ascending, descending, etc.), etc IF your invoice numbers are... numbers only (
but I see that you have a SO01, a mix of numbers and letters -- OK that was in the sample grid...
).
The "parents way" looks good to me (probably the bes)... Well : each work could be a parent, and its subitems would correspond to multiple invoices. You'd have only one invoice field, and it would be easy to sort all invoices in "flat view" or even "hierarchical view", depending on your needs. You could have the itemparent field to be displayed in your grid if you choose such a way : it might facilitate seeing which invoice goes with which work (in flat view, for example...).
In any case, you might also have to create a date field called LastInvoiceDate (or whatever), that you'd edit yourself each time you add a new invoice (you could also just rely on the "itemCreated" field if you use the "Parent" way.)
IF you don't want to create a new field for each invoice or use the parent way maybe you could try to type the different invoice numbers in the same field, as you suggested? (And also, of course create the date field called LastInvoiceDate that you'd have to edit yourself each time you add a new invoice.)
For that way you'd have to :
1- Create a Invoice
multi-line and
text field (in the "Manage field" window),
2- Create a LastInvoiceDate
date field
Close the grid and reopen it to be able to activate the multi-line field (I believe that it's a bug in the Grid component)
Now, you could write each invoice number bellow the previous one (write the first one,
shift+enter, then the other one, etc.), and maybe add a prefix to these numbers like : "a-", "b-", etc. (so you'll be able to easily find all "b" invoices, and see how many items have been billed 2 times, etc.
Sorting and filtering ?
--> Use a field-column filter to see specific invoice # : *b-*,*200*, or whatever...
--> Use the filter/source bar to see specific invoice numbers.
ie :
-
Invoice alike "a-%" (will show all items-invoices starting with "a-")
-
Invoice alike "%-2%" (will show all items-invoices starting with "-2")
[edit : before, i wrote category instead of invoice!!!! sorry : i was thinking in terms of my own grid!]
with this way, I don't think that it would be feasible to sort your invoices or items by number.
