SQL查詢JOIN和WHERE

Question

我越來越想在我查詢以獲得一個特定的值時，下面的消息

「指定的域可以是指多個表」

這是很清楚的我正在嘗試搜索多個表格中存在的內容，但如何正確執行此操作？

現在我有以下代碼：

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 

的最後一句話是問題...任何想法？

Answer 1

錯誤消息非常明確，WHERE子句WHERE CustomerId = 0015中的字段CustomerId在兩個表中都顯示。你必須確定你想從哪個表中使用它; 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

您應該指向什麼表是從WHERE語句

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

你需要從你需要客戶ID哪個表並初始化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