UPDATE meta.toShow SET toShow = '1';
UPDATE meta.pnrList PL 
INNER JOIN 
( SELECT PNR, Timestamp FROM PNR_Trigger.PNR_Ticket_Details GROUP BY PNR ORDER BY DATE(Timestamp) DESC, Timestamp DESC) A
ON PL.PNR = A.PNR 
SET PL.Timestamp = A.Timestamp ;