if you have a telephone field in a table where numbers have been entered in the format 1234567890 then use this to format it as 123-456-7890
select
o.orderid,
o.status,
o.b_country,
o.phone,
CONCAT(LEFT(o.phone, 3), '-', MID(o.phone, 4, 3), '-', RIGHT(o.phone, 4)) AS 'formatted_phone'
from
orders as o
where
o.b_country IN ('US','CA','PR')
and length(o.phone) = 10
order by o.orderid desc
limit 100