请帮我优化这个查询:SQL查询优化与NOT IN语句
$result = mysql_query('
SELECT DISTINCT caseNumber
FROM master_break
WHERE invoiceNumber='$invoice'
AND bay='$bay' AND caseNumber
NOT IN(SELECT DISTINCT caseNumber
FROM shipped_data
WHERE status='' AND bay='$bay')
ORDER BY caseNumber ASC");
感谢。
'''最后来自哪里? – Amy