SELECT min_Ds as Ds countdistinct appid as app_count FROM select AppIdentifier as appid minDs as min_Ds from log_iMonkey_iOS_overview

您可以尝试将PlatformType转换为字符串类型，以便与AppIdentifier的数据类型匹配。请尝试以下修改后的代码：

SELECT min_Ds AS Ds,
       COUNT(DISTINCT appid) AS app_count
FROM (
    SELECT AppIdentifier AS appid,
           min(Ds) AS min_Ds
    FROM log_iMonkey_iOS_overview
    GROUP BY AppIdentifier
    UNION ALL
    SELECT AppIdentifier AS appid,
           min(Ds) AS min_Ds
    FROM log_iMonkey_Android_overview
    GROUP BY AppIdentifier
    UNION ALL
    SELECT CAST(PlatformType AS String) AS appid,
           min(Ds) AS min_Ds
    FROM log_iMonkey_Android_overview
    GROUP BY PlatformType
) subquery

请注意，我在第三个子查询中使用了CAST(PlatformType AS String)将PlatformType转换为字符串类型。这样，所有三个子查询返回的数据类型就会一致，避免了类型不匹配的错误