我在Access DB的VB应用程序中有此查询：

  SELECT DISTINCT Specialization, MAX(a.faultZone) AS faultZone, ISNULL(a.faultCount, 0) AS NoOfFaults  FROM Technicians AS t 
    LEFT JOIN 
             ( 
            SELECT DISTINCT Faults.[Type] AS faultType, MAX(Faults.[Zone]) AS faultZone, COUNT(Faults.[Type]) AS faultCount 
            FROM Faults "
            WHERE Faults.[Zone] = 8 " ' this value will be from variable
            GROUP BY Faults.[Type] "
            ) AS a 
    ON (t.Specialization = a.faultType) 
    WHERE t.specialization <> 'None' "
    GROUP BY a.faultCount, t.Specialization

它给出了我无法解决的以下问题…

“查询表达式’ISNULL（a.faultCount，0’）中的函数使用的参数数量错误。”

我要实现的只是将值设置NoOFFaults为零，这意味着在特定区域中没有故障。

谢谢你