INSERT INTO history(staid, stype, sdate, svalue) VALUES( '53357', 1, '2022-06-20 10:00:00', 0.1)
ON DUPLICATE KEY
UPDATE svalue = 0.3
PHP运用效果
$db->query('INSERT INTO history(staid, stype, sdate, svalue) VALUES(\''.$staid.'\', 1, \''.date('Y-m-d H:00:00', strtotime($rain2[$i][0])).'\', '.floatval($rain2[$i][1]).') ON DUPLICATE KEY UPDATE svalue = ' . $rain2[$i][1]);