Question

我有桌子，我想加入。它们与客户匹配号和客户匹配号相关联。我想从一个表中输入数据，然后与另一个表连接，然后显示第二个表中的结果。我的代码如下所示：

SELECT [title], 
       [customer_no], 
       [forename], 
       [surname], 
       [res_addr_1], 
       [res_addr_2], 
       [city],   
       [country], 
       [res_postcode], 
       [DOB], 
       [Home_phone_no], 
       [Mobile_phone_no] 
 FROM Customer
 LEFT JOIN Account ON cust_match_no 
      FROM Customer = customer_match_no 
      FROM Account  
 WHERE Account.account_no = '12345678';

但是我在“=”附近的语法不正确时出现错误，我不明白为什么！

Answer 1

这不是FROM子句的目的。 FROM指定查询中的“主”表。为了指定JOIN中哪些表应该匹配哪些字段，如果存在歧义，则需要使用表的名称或别名来限定这些字段，就像使用WHERE子句一样：WHERE Account.account_no = ... 。在您的情况下，似乎没有必要，因为来自Account的字段名为cust_match_no而另一个字段是customer_match_no，但无论如何您可以像这样重写您的查询：

SELECT 
    [title], 
    [customer_no], 
    [forename], 
    [surname], 
    [res_addr_1], 
    [res_addr_2], 
    [city], 
    [country], 
    [res_postcode], 
    [DOB], 
    [Home_phone_no], 
    [Mobile_phone_no] 
FROM Customer cus
LEFT JOIN Account acc ON cus.cust_match_no = acc.customer_match_no
WHERE acc.account_no = '12345678';

如果SELECT子句中的列名不明确，则适用相同的建议。假设客户和账户表中都有一个“国家/地区”字段。然后，您应该对这些列进行限定以消除歧义：

SELECT
    [Customer].[Country],
    [Account].[Country]
    ....

PS。请原谅我的英文

Answer 2

SELECT [title], [customer_no], [forename], [surname],
[res_addr_1], [res_addr_2], [city], [country], [res_postcode], 
[DOB], [Home_phone_no], [Mobile_phone_no] FROM Customer
LEFT JOIN Account ON 
cust_match_no = customer_no WHERE Account.account_no = '12345678';

Answer 3

尝试这样：

SELECT 
    [title],
    [customer_no], 
    [forename], 
    [surname], 
    [res_addr_1], 
    [res_addr_2], 
    [city], 
    [country], 
    [res_postcode], 
    [DOB], 
    [Home_phone_no], 
    [Mobile_phone_no] 
FROM 
    Customer 
LEFT JOIN 
    Account 
ON 
    cust_match_no = customer_match_no 
WHERE 
    Account.account_no = '12345678'

Answer 4

         SELECT [title], [customer_no], [forename], [surname], [res_addr_1], [res_addr_2], 
[city],   [country], [res_postcode], [DOB], [Home_phone_no], [Mobile_phone_no] FROM Customer
LEFT JOIN Account ON Account.cust_match_no = Customer.customer_match_no 
WHERE Account.account_no = '12345678';

Answer 5

试试这样：

SELECT [title], 
   [customer_no], 
   [forename], 
   [surname], 
   [res_addr_1], 
   [res_addr_2], 
   [city],   
   [country], 
   [res_postcode], 
   [DOB], 
   [Home_phone_no], 
   [Mobile_phone_no] 
FROM Customer
LEFT JOIN Account ON cust_match_no = customer_match_no    
WHERE Account.account_no = '12345678';

语法错误SQL连接语句

5 个答案: