Sql Access 2010:查询表达式中的语法错误（缺少运算符）

我想在sql查询中有三个表，但收到一条错误消息

我有以下sql代码：

 SELECT warehouse.expiry_date, pharmacy.expiry_date, drugs.active_substance, 
 drugs.strength, drugs.strength_type, drugs.dosage_form, drugs.minimum_quantity, 
 SUM(warehouse.in_quant)+SUM(pharmacy.in_quant)-SUM(warehouse.out_quant)-
 SUM(pharmacy.out_quant) AS Total_available_stock

 FROM drugs as a 
  INNER JOIN warehouse as b
    ON a.ID = b.drug_id 
  INNER JOIN pharmacy as c 
    ON b.drug_id = c.drug_id
 GROUP BY warehouse.expiry_date, pharmacy.expiry_date, drugs.active_substance, 
 drugs.strength, drugs.strength_type, drugs.dosage_form, drugs.minimum_quantity;

我得到了一个错误：

 Syntax error (missing operator) in query expression in 'a.ID = b.drug_id 
 INNER JOIN pharmacy as c
     on b.drug_id = c.drug_i'.

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有什么帮助吗？

在Access中，当您有多个连接时，您需要括号：

FROM (drugs as a 
  INNER JOIN warehouse as b
    ON a.ID = b.drug_id) 
  INNER JOIN pharmacy as c 
    ON b.drug_id = c.drug_id

---

只是想补充一点，当你有两个以上的内部连接时，它会变得更加混乱。然后，您需要在每个内部联接的开头和结尾添加一个额外的括号（最后一个除外）

例如：

 FROM ((drugs as a 
  INNER JOIN warehouse as b
    ON a.ID = b.drug_id) 
  INNER JOIN pharmacy as c1 
    ON b.drug_id1 = c1.drug_id)
  INNER JOIN pharmacy as c2 
    ON b.drug_id2 = c2.drug_id

---

非常感谢。毫无意义的偏执，这是看不起Access的另一个原因。荒唐的Thonx.@Dave.Gugg，微软的SQL Server没有同样的问题，它实际上相当不错。不过，我更喜欢MySQL。十年后，这种愚蠢的需求仍然很强烈。