select with left join and null values

[pelegk2]

when i make a select using LEFT JOIN
i recive on some rows null - which is ok!
can i instead of the null write a string of my own?
that in case of a null value write for example "zzz"?
thnaks in adane
peleg

[tomhath]

select coalesce(myColumn, 'zzz')
from myTable

[pelegk2]

SELECT distinct P_makat_RAW,prod_name,if (tblweightstations.set_no is null,'99',tblweightstations.set_no) as station_num FROM uniprod.tblweighing.....................................