Question

我有一个Customer表和一个Address表。

Address表有一个INVOICE，CORRESPONDENCE或DELIVERY标志。

客户可以拥有0到多个地址记录。

我希望能够查询两个表并根据地址数据为每个客户生成一个标志 - 没有地址记录= NONE，1个或多个INVOICE记录= HASINVOICE，没有INVOICE但是1个或更多其他= HASOTHER

所以，对于以下数据：

+------------+---------+
| CustomerID |  Name   |
+------------+---------+
|          1 | Peter   |
|          2 | Ray     |
|          3 | Egon    |
|          4 | Winston |
|          5 | Dana    |
+------------+---------+

+-----------+------------+----------------+
| AddressID | CustomerID |  AddressType   |
+-----------+------------+----------------+
|         1 |          1 | INVOICE        |
|         2 |          1 | DELIVERY       |
|         3 |          2 | DELIVERY       |
|         4 |          2 | CORRESPONDENCE |
|         5 |          4 | INVOICE        |
|         6 |          5 | CORRESPONDENCE |
+-----------+------------+----------------+

我希望得到以下结果：

+------------+---------+-------------+
| CustomerID |  Name   | AddressFlag |
+------------+---------+-------------+
|          1 | Peter   | HASINVOICE  |
|          2 | Ray     | HASOTHER    |
|          3 | Egon    | NONE        |
|          4 | Winston | HASINVOICE  |
|          5 | Dana    | HASOTHER    |
+------------+---------+-------------+

对于SQL 2000，是否可以使用单个查询而不使用游标？

Answer 1

我没有方便的2000实例（你真的应该升级，你落后4-5版本），但我认为这应该有效：

declare @Customers table (CustomerID int,Name varchar(10))
insert into @Customers (CustomerID,Name)
select 1,'Peter' union all    select 2,'Ray' union all
select 3,'Egon' union all    select 4,'Winston' union all
select 5,'Dana'

declare @Addresses table (AddressID int, CustomerID int,
                          AddressType varchar(30))
insert into @Addresses (AddressID,CustomerID,AddressType)
select 1,1,'INVOICE' union all    select 2,1,'DELIVERY' union all
select 3,2,'DELIVERY' union all    select 4,2,'CORRESPONDENCE' union all
select 5,4,'INVOICE' union all    select 6,5,'CORRESPONDENCE'

select
    c.CustomerID,
    c.Name,
    CASE MAX(CASE 
        WHEN a.AddressType = 'Invoice' THEN 2
        WHEN a.AddressType IS NOT NULL THEN 1
        END
    ) WHEN 2 THEN 'HASINVOICE'
    WHEN 1 THEN 'HASOTHER'
    ELSE 'NONE'
    END as AddressFlag
from
    @Customers c
        left join
    @Addresses a
        on
            c.CustomerID = a.CustomerID
group by
    c.CustomerID,
    c.Name

产地：

CustomerID  Name       AddressFlag
----------- ---------- -----------
5           Dana       HASOTHER
3           Egon       NONE
1           Peter      HASINVOICE
2           Ray        HASOTHER
4           Winston    HASINVOICE

SQL select标志基于连接表的计数和/或标志

1 个答案: