How many engineer visits are required at most for a single fault log? List the number and the log entry id.
create table fault_log (fault_log_entry_id varchar, PRIMARY KEY (fault_log_entry_id)); create table engineer_visits (fault_log_entry_id varchar, PRIMARY KEY (fault_log_entry_id))
select count(*), t1.fault_log_entry_id from fault_log as t1 join engineer_visits as t2 on t1.fault_log_entry_id = t2.fault_log_entry_id group by t1.fault_log_entry_id order by count(*) desc limit 1