Question

尝试在查询中获取特定值时，我收到以下消息

“指定的字段可以引用多个表”

很明显，我正在尝试搜索多个表中存在的内容，但是如何做到这一点呢？

现在我有以下代码：

SELECT Table1.CustomerId, Table1.Address, 
       Table2.CustomerId, Table2.Telephone, 
       Table3.CustomerId, Table3.Notes
FROM (Table1 INNER JOIN Table2 ON Table1.CustomerId=TAble2.CustomerId) 
      INNER JOIN Table3 ON Table2.CustomerId=Table3.CustomerId
WHERE CustomerId = 0015

最后一句是问题......任何想法？

Answer 1

错误消息非常清楚，CustomerId子句WHERE中的字段WHERE CustomerId = 0015显示在两个表中。您必须确定要从哪个表中使用它; table1或table2？例如：

SELECT Table1.CustomerId, Table1.Address, 
       Table2.CustomerId, Table2.Telephone, 
       Table3.CustomerId, Table3.Notes
FROM (Table1 INNER JOIN Table2 ON Table1.CustomerId=TAble2.CustomerId) 
      INNER JOIN Table3 ON Table2.CustomerId=Table3.CustomerId
WHERE table1.CustomerId = 0015

Answer 2

您应该在WHERE语句

中指出哪个表是CustomerId

SELECT Table1.CustomerId, Table1.Address, 
       Table2.CustomerId, Table2.Telephone, 
       Table3.CustomerId, Table3.Notes
FROM (Table1 INNER JOIN Table2 ON Table1.CustomerId=TAble2.CustomerId) 
      INNER JOIN Table3 ON Table2.CustomerId=Table3.CustomerId
WHERE Table1.CustomerId = 0015

Answer 3

您需要初始化您需要客户ID的表。

SELECT Table1.CustomerId, Table1.Address, 
       Table2.CustomerId, Table2.Telephone, 
       Table3.CustomerId, Table3.Notes
FROM (Table1 INNER JOIN Table2 ON Table1.CustomerId=TAble2.CustomerId) 
      INNER JOIN Table3 ON Table2.CustomerId=Table3.CustomerId
WHERE table1.CustomerId = 0015

使用INNER JOIN和WHERE进行SQL查询

3 个答案: