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