排除一对多查询的结果

Question

我很难从一对多 table 关系中提取数据。 我需要列出尚未应用 "Echo" 保修代码的设备合同列表。 在我的场景中，我有一份设备合同 table 和一份保修单 table。

设备合同table（以下简称EQC）的设计是：


------------------------------------------------------------------------------------
| EquipmentID  | Contract  | SerialNumber | Make | Model | Date         | Customer |
------------------------------------------------------------------------------------
| 001          | A1        | GDS12        | GRND | GR219 | 2016-03-02   | Acme Corp|
| 002          | B1        | BQWSD        | BQW  | BLU22 | 2016-03-10   | Fast Lawn|
| 003          | C1        | Foo36        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 004          | D1        | Foo37        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 005          | E1        | Foo38        | Foo  | Red18 | 2016-03-01   | Perfect T|
------------------------------------------------------------------------------------

质保书table（以下简称WAR）的设计为：


---------------------------------------------------
| SerialNum | Make  | WarrantyCode | Warranty Date|
---------------------------------------------------
| GDS12     | GRND  | Alpha        | 2016-04-01   |
| GDS12     | GRND  | Bravo        | 2016-04-01   |
| GDS12     | GRND  | Delta        | 2016-04-01   |
| GDS12     | GRND  | Charlie      | 2016-04-01   |
| GDS12     | GRND  | Echo         | 2016-04-01   |
| BQWSD     | BQW   | Alpha        | 2016-04-01   |
| BQWSD     | BQW   | Bravo        | 2016-04-01   |
| BQWSD     | BQW   | Charlie      | 2016-04-01   |
| BQWSD     | BQW   | Foxtrot      | 2016-04-01   |
| BQWSD     | BQW   | Echo         | 2016-04-01   |
| Foo36     | Foo   | Alpha        | 2016-04-01   |
| Foo36     | Foo   | Bravo        | 2016-04-01   |
| Foo36     | Foo   | Charlie      | 2016-04-01   |
| Foo36     | Foo   | Hotel        | 2016-04-01   |
---------------------------------------------------

我需要做的是列出尚未应用 "Echo" 保修代码的 EQC。也就是说要么没有Echo记录，要么还没有保修记录期。

我的结果集应该如下所示：


------------------------------------------------------------------------------------
| EquipmentID  | Contract  | SerialNumber | Make | Model | Date         | Customer |
------------------------------------------------------------------------------------
| 003          | C1        | Foo36        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 004          | D1        | Foo37        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 005          | E1        | Foo38        | Foo  | Red18 | 2016-03-01   | Perfect T|
------------------------------------------------------------------------------------

（GDS12 和 BQWSD 被排除在外，因为它们应用了 Echo 保修代码。）

我的查询是：

SELECT EQC.EquipmentID
  ,EQC.Contract
  ,EQC.SerialNumber
  ,EQC.Make
  ,EQC.Model
  ,EQC.DATE
  ,EQC.Customer
FROM equipment - contracts EQC
LEFT JOIN warranty WAR
  ON WAR.SerialNum = EQC.SerialNumber
    AND WAR.Make = EQC.Make
WHERE WAR.WarrantyCode is null 
  OR WAR.WarrantyCode <> 'Echo'

结果集如下所示：


------------------------------------------------------------------------------------
| EquipmentID  | Contract  | SerialNumber | Make | Model | Date         | Customer |
------------------------------------------------------------------------------------
| 001          | A1        | GDS12        | GRND | GR219 | 2016-03-02   | Acme Corp|
| 001          | A1        | GDS12        | GRND | GR219 | 2016-03-02   | Acme Corp|
| 001          | A1        | GDS12        | GRND | GR219 | 2016-03-02   | Acme Corp|
| 001          | A1        | GDS12        | GRND | GR219 | 2016-03-02   | Acme Corp|
| 002          | B1        | BQWSD        | BQW  | BLU22 | 2016-03-10   | Fast Lawn|
| 002          | B1        | BQWSD        | BQW  | BLU22 | 2016-03-10   | Fast Lawn|
| 002          | B1        | BQWSD        | BQW  | BLU22 | 2016-03-10   | Fast Lawn|
| 002          | B1        | BQWSD        | BQW  | BLU22 | 2016-03-10   | Fast Lawn|
| 003          | C1        | Foo36        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 003          | C1        | Foo36        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 003          | C1        | Foo36        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 003          | C1        | Foo36        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 004          | D1        | Foo37        | Foo  | Red18 | 2016-03-04   | Perfect T|
| 005          | E1        | Foo38        | Foo  | Red18 | 2016-03-01   | Perfect T|
------------------------------------------------------------------------------------

Answer 1

您想要 不存在的 EQC 一个 Echo WAR。或者换句话说：您想要不在 Echo WAR 集合中的 EQC。

select *
from equipment eqc
where not exists
(
  select *
  from warranty war
  where war.serialnum = eqc.serialnumber
  and war.make = eqc.make
  and war.warrantycode = 'Echo'
);

或者：

select *
from equipment
where (serialnumber, make) not in
(
  select serialnum, make
  from warranty
  where warrantycode = 'Echo'
);

更新： 但是，我不确定 SQL 服务器是否支持 IN 子句中的元组，如上所示。正如您所见，这是一个很棒的功能，它使查询真正可读，但不幸的是，某些 DBMS 不支持此语法。

排除一对多查询的结果

Excluding results from One to Many query

sql

sql-server

inner-join

outer-join