SELECT h.itemid,h.value,h.clock FROM history_uint h 
JOIN (SELECT h2.itemid,h2.clock,MAX(h2.ns) AS ns FROM history_uint h2 
JOIN (SELECT itemid,MAX(clock) AS clock FROM history_uint WHERE itemid=50709419 AND clock>='1745856891' AND clock<='1745867691' GROUP BY itemid) s2 
ON h2.itemid=s2.itemid AND h2.clock=s2.clock GROUP BY h2.itemid,h2.clock) s 
ON h.itemid=s.itemid AND h.clock=s.clock AND h.ns=s.ns