двойной ордер бай

SELECT catalog.image_catalog, catalog.chpu AS cchpu, catalog.param2 AS cparam2, catalog.id AS cid, catalog.code AS ccode, catalog.marka AS cmarka, catalog.cost4 AS ccost, catalog.curr AS ccurr, prigroup.name AS pname, biggroup.info AS binfo, biggroup.name AS bname

FROM catalog, prigroup, biggroup, subgroup

WHERE catalog.group3 = subgroup.id

AND prigroup.id = catalog.group2

AND biggroup.id = catalog.group1

AND biggroup.id = '1'

ORDER BY ccost = '0', ccost ASC  

 

ORDER BY ccost = '0', ccost ASC - отсортировал по цене,

но я хочу отсортировать еще по одному параметру! param2 - типо наличие на складе.

как еще один ордер бай присобавить??? т.е. двойной ордер бай сделать??

order by param2