Narrow A First Set Of Records

Hey gang,

I need the ability to produce this end result:

condition a) All clients who have had at least 2 appointments in the last 24 months
condition b) of the set of “condition a” rows, which of those have NO appointments in the last 6 months

I am able to get the clients with >= 2 appointments with this query

SELECT 
c.client_id, 
concat(c.first_name, ' ', c.last_name) AS client_name,
c.`address`, 
c.city, 
c.state, 
c.`zip`, 
c.email , 
max(from_unixtime(a.time_start)) AS last_appt,
count(a.client_id) AS appt_count

FROM tl_clients c
LEFT JOIN tl_appt a ON c.client_id = a.client_id
GROUP BY a.client_id
HAVING max(a.time_start) >= UNIX_TIMESTAMP(DATE_SUB( NOW(), INTERVAL 24 MONTH))
AND last_appt IS NOT NULL AND count(a.client_id) >= 2;

BUT, how do I add the other “condition b” to the query to get an accurate end result.

I’d appreciate any help.

Don