Sql 三向内部联接的查询表达式中出现语法错误（缺少运算符）

我看到以下错误消息：查询表达式'm.AccountNumber=a.AccountNumber'中的语法错误（缺少运算符） 将以下查询写入我的VBA程序时，a.AccountNumber=b.AccountNumber'上的内部联接活动表\u 2M b：

SELECT m.CaseManager, SUM(m.Lead) AS 'Total Leads', 
COUNT(a.Description) AS 'Total Activity', 
COUNT(b.Description) AS 'Total Activity (T-2 Months)', 
Sum(IIF(a.Description Like 'Outgoing Call%',1,0)) As 'Outbound Calls', 
Sum(IIF(b.Description Like 'Outgoing Call%',1,0)) As 'Outbound Calls (T-2 Months)', 
Sum(IIF(a.Description Like 'Credit%',1,0)) As 'Credit', 
Sum(IIF(b.Description Like 'Credit%',1,0)) As 'Credit (T-2 Months)', 
Sum(IIF(a.Description Like 'Correspondence Sent%',1,0)) As 'Correspondence', 
Sum(IIF(b.Description Like 'Correspondence Sent%',1,0)) As 'Correspondence (T-2 Months)' 
FROM AccountTable m INNER JOIN ActivityTable a ON m.AccountNumber=a.AccountNumber 
INNER JOIN ActivityTable_2M b On a.AccountNumber = b.AccountNumber 
GROUP BY m.CaseManager;

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在我添加第二个内部联接（ActivityTable_2M）之前，查询运行良好，因此我假设这其中存在问题。我在SQL测试仪上运行了此查询，没有突出显示任何错误。

在access中，当使用多个联接时，需要使用括号

（）

。请试试这个：

SELECT m.CaseManager, SUM(m.Lead) AS 'Total Leads', 
COUNT(a.Description) AS 'Total Activity', 
COUNT(b.Description) AS 'Total Activity (T-2 Months)', 
Sum(IIF(a.Description Like 'Outgoing Call%',1,0)) As 'Outbound Calls', 
Sum(IIF(b.Description Like 'Outgoing Call%',1,0)) As 'Outbound Calls (T-2 Months)', 
Sum(IIF(a.Description Like 'Credit%',1,0)) As 'Credit', 
Sum(IIF(b.Description Like 'Credit%',1,0)) As 'Credit (T-2 Months)', 
Sum(IIF(a.Description Like 'Correspondence Sent%',1,0)) As 'Correspondence', 
Sum(IIF(b.Description Like 'Correspondence Sent%',1,0)) As 'Correspondence (T-2 Months)' 
FROM (AccountTable m INNER JOIN ActivityTable a ON m.AccountNumber=a.AccountNumber) 
INNER JOIN ActivityTable_2M b On a.AccountNumber = b.AccountNumber 
GROUP BY m.CaseManager;

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在access中，如果不使用括号分隔连接，则不能有多个连接。参考资料：

在MS Access中，连接两个以上的表时需要使用括号。语法来自tableA内部联接（tableB内部联接tableC）@Danny O'Sullivan如果您仍然面临此查询的任何问题，请告诉我。