Question

我是sql的新手，我正在尝试连接两个表并合并值。单独运行时，下面的Coalesce代码可以正常工作

Select  @ContactName = COALESCE(@ContactName + ', ', '') + c.ContactName from contacts  c inner join  functions b on c.pid= b.pid

但是当我把整个代码组合起来时，它没有执行。有人可以建议如下。

 select 
a.*,
b.tfunction, 
b.SSummary,
b.ContactType,
(  Select  @ContactName = COALESCE(@ContactName + ', ', '') + c.ContactName from contacts  c inner join  functions b on c.pid = b.pid),
(   Select  @Address = COALESCE(@Address + ', ', '') + c.Address from contacts  c inner join  functions b on c.pid = b.pid),
(  Select  @ContactPhone = COALESCE(@ContactPhone + ', ', '') + c.ContactPhone from contacts  c inner join  functions b on c.pid = b.pid),
(    Select  @ContactEmail = COALESCE(@ContactEmail + ', ', '') + c.ContactEmail from contacts  c inner join  functions b on c.pid = b.pid)
from contracts a
inner join functions b on a.pid = b.pid

错误详情

Msg 102, Level 15, State 1, Line 12
Incorrect syntax near '='.
Msg 102, Level 15, State 1, Line 13
Incorrect syntax near ','.
Msg 102, Level 15, State 1, Line 14
Incorrect syntax near ','.
Msg 102, Level 15, State 1, Line 15
Incorrect syntax near ')'.

ps： - 随意修改代码。

PS-我有所有4个属性的声明变量 - 堆栈溢出不允许我出于某种原因粘贴它们。

Answer 1

这是您的查询：

 select a.*, b.tfunction, b.SSummary, b.ContactType,
        (Select  @ContactName = COALESCE(@ContactName + ', ', '') + c.ContactName
         from contacts  c inner join 
              functions b
              on c.pid = b.pid
        ),
        (Select  @Address = COALESCE(@Address + ', ', '') + c.Address
         from contacts  c inner join
              functions b
              on c.pid = b.pid
        ),
        (Select @ContactPhone = COALESCE(@ContactPhone + ', ', '') + c.ContactPhone
         from contacts  c inner join 
              functions b
              on c.pid = b.pid
        ),
        (  varchar(1000)  Select  @ContactEmail = COALESCE(@ContactEmail + ', ', '') + c.ContactEmail
         from contacts  c inner join
              functions b
              on c.pid = b.pid
         )
from contracts a inner join
     functions b
     on a.pid = b.pid;

这有多个明显的语法错误：

您无法在子查询中设置变量值。实际上，查询不能同时返回行并设置变量值。
varchar(1000)只是挂在那里，好像你试图用C或其他东西进行演员。

然后你有其他逻辑错误：

在同一声明中分配和使用变量。
返回多行的子查询。
在看起来相关的子查询中缺乏相关性。

您似乎想要从联系人处获取事物列表。这在SQL Server中很痛苦，但这可能会让您走上正确的道路：

 select a.*, b.tfunction, b.SSummary, b.ContactType,
        stuff((select ', ', c.ContactName
               from contacts c
               where c.pid = b.pid
               for xml path ('')
              ), 1, 2, '') as Contacts,
        stuff((Select ', ' + c.Address
                from contacts c
                where c.pid = b.pid
                for xml path ('')
              ), 1, 2, '') as Addresses,
         . . .
from contracts a join
     functions b
     on a.pid = b.pid;

Answer 2

问题可能在于您的INNER JOIN，FUNCTIONS中必须有一行才能看到任何结果。

如果您想要显示CONTACTS中的行，即使FUNCTIONS中的行不匹配，也要将INNER JOIN替换为LEFT JOIN。

Select  
    @ContactName = COALESCE(@ContactName + ', ', '') + c.ContactName 
from contacts  c 
LEFT join  functions b on c.pid= b.pid

Sql Query连接表和合并值

2 个答案: