correct syntax for multiple sql query

[Alistair]

hello again people...

Access2000, IIS6, win XP pro

I have a form where users can enter search criteria for various products.

now, if this form has 2 fields, colour and size (it wil have more but I'm
assuming the the principle for two fields will be the same for ten fields)

what would be the correct syntax for performing a query where the user
didn't enter a criteria for both fields?

the search string would be

strSQL = "SELECT * FROM products where colour = " & "'" &
request.form("searchstrcolour") & "'" & "AND size =" & "'"
request.form("searchstrsize") & "'" & " ORDER by price"

so if the user selects blue and large, thats fine

but what if the user only selected say blue and didn't bother with the size?

is there a wild card that I could use?

many thanks