Question

sql server：2012

这是3张桌子。

第一个表是用户（顾问）表第二个是价格表，第一列的每个用户都有一个价格最后一张表定义了顾问提供服务的区域（城市）

Consultants      Prices           Area
uid | Name       uid | Price      uid | City
----|-----      -----|-------     ----|------
1   | Dave        1  |  5           1 | NY
2   | Adrian      2  |  7           1 | LA
3   | John        4  |  5           4 | NY
4   | Lee                           4 | NO
                                    4 | LA 
                                    4 | SF

我需要从所有表格中选择这样的内容：

uid  |  Price   | City
-----|----------|-------
 1   |    5     | NY, LA
-----|----------|-------
 2   |    7     | 
-----|----------|-------
 4   |    5     | NY, NO, LA, SF
-----|----------|-------

我该如何选择？有什么想法吗？

Answer 1

由于未指定数据库，假设SQL Server 2008，您可以使用STUFF function和Group BY Clause将多行合并为单个逗号分隔值

Select C.uid, P.price, ISNULL(A.City,'') City
From Consultants C
     INNER JOIN Prices P ON C.uid = P.uid
     LEFT JOIN (
                 SELECT  UID
                         ,STUFF((SELECT ', ' + CAST(city AS VARCHAR(10)) [text()]
                         FROM Area
                         WHERE UID = t.UID
                         FOR XML PATH(''), TYPE)
                         .value('.','NVARCHAR(MAX)'),1,2,' ') CITY
                  FROM Area t
                  GROUP BY UID ) A 
      ON C.uid = A.uid

Working SQL Fiddle

Answer 2

也许你可以这样做

declare @consultants table (uid int,name varchar(10))
insert into @consultants (uid,name)values (1,'dave'),(2,'adrian'),(3,'jon'),(4,'lee')
declare @Prices table (uid int,price int)
insert into @Prices(uid,price)values (1,5),(2,7),(4,5)

declare @Area table (uid int,city varchar(5))
insert into @Area(uid,city)values (1,'NY'),(1,'LA'),(4,'NY'),(4,'LA'),(4,'SF'),(4,'NO')

select t.uid,tt.price,ISNULL(STUFF((select  +', '+ city from @Area where uid = t.uid FOR XML PATH(''), TYPE)
                         .value('.','NVARCHAR(MAX)'),1,2,' '),'')CITY  from @consultants t INNER JOIN @Prices tt
ON t.uid = tt.uid

sql查询加入和连接值

2 个答案: