Mysql SELECT: possible to concantenate fields ONLY if they contain data?

I have a database driven eCommerce site, that captures address info in three fields:

Address1
Address2
Address3

However, my fulfilment provider only accepts two fields:

Address1
Address2

I have been able to CONCAT Address2 and Address3, placing ', ' in between them - however, if there is no Address2 or no Address3 this results in a pointless comma, which breaks the fulfilment system!

Is it possible to somehow check if Address2 and Address3 contain data, and only then CONCAT with a comma in between them?

Here's the query in use at the moment:

 

SELECT o.id AS orderID, o.shiptotal AS fPostageCost, CONCAT(o.dateyear,'-',o.datemonth,'-',o.dateday) AS dReceievedDate, o.ordertotal AS fTotalCharge, o.taxctotal AS fTax, 'GBP' AS cCurrency, '' AS PostalServiceTag, o.id AS ReferenceNum, CONCAT(oi.fname,' ',oi.lname) AS cFullName, o.customtwo AS cShippingAddress, oi.postalcode AS cPostCode, oi.country AS Country, o.email AS cEmailAddress, '' AS PackagingGroup, o.customone AS addCompany, CONCAT(oi.fname,' ',oi.lname) AS addName, oi.addone AS addAddress1, CONCAT(oi.addtwo,', ',oi.addthree) AS addAddress2, oi.city AS addTown, oi.stateprov AS addCounty, oi.country AS addCountry, oi.postalcode AS addPostCode, o.phone AS CustomerPhoneNumber
FROM ecom_orders o, ecom_orderitems oi WHERE status = 'NS' AND o.id = oi.orderid GROUP BY o.id

Select all Open in new window