select countDISTINCT AppIdentifier from log_iMonkey_iOS_overviewWHERE TimeStamp = subtractDaystoDatenow 30union allselect countDISTINCT PlatformType from log_iMonkey_Android_overviewWHERE TimeStamp =

你可以使用子查询和UNION ALL操作符来实现这个目标。以下是一个可能的解决方案：

SELECT SUM(cnt) AS total_count FROM ( SELECT COUNT(DISTINCT AppIdentifier) AS cnt FROM log_iMonkey_iOS_overview WHERE TimeStamp >= subtractDays(toDate(now()), 30) UNION ALL SELECT COUNT(DISTINCT PlatformType) AS cnt FROM log_iMonkey_Android_overview WHERE TimeStamp >= subtractDays(toDate(now()), 30) AND PlatformType != 0 ) AS subquery