尝试在MySQL中执行减号操作 [英] Trying to perform MINUS operation in MySQL

问题描述

我试图在MySql中执行MINUS操作.我有三个表:

I am trying to perform a MINUS operation in MySql.I have three tables:

1. 一个提供服务详细信息
2. 一张表，其中说明要在其中提供服务
3. 另一个表(基于邮政编码和状态)显示了不提供此服务的位置.

我能够分别获得这两个选择查询的输出.但是我需要一个合并的语句，将输出作为 "SELECT查询_1-SELECT查询_2".

I am able to get the output for those two select queries separately. But I need a combined statement that gives the output as 'SELECT query_1 - SELECT query_2'.

服务详细信息表 Service_Code(PK)服务名称

Service_Details Table Service_Code(PK) Service Name

服务状态表 Service_Code(FK)州国家PK(Service_Code，州，国家)

Servicing_States Table Service_Code(FK) State Country PK(Service_Code,State,Country)

例外表 Service_Code(FK)邮政编码状态PK(Service_Code，邮政编码，状态)

Exception Table Service_Code(FK) Zipcode State PK(Service_Code,Zipcode,State)

推荐答案

MySql无法识别 MINUS 和 INTERSECT ，这些都是基于Oracle的操作.在MySql中，用户可以将NOT IN用作MINUS(也有其他解决方案，但我非常喜欢它). 示例:

MySql does not recognise MINUS and INTERSECT, these are Oracle based operations. In MySql a user can use NOT IN as MINUS (other solutions are also there, but I liked it lot). Example:

select a.id 
from table1 as a 
where <condition> 
AND a.id NOT IN (select b.id 
                 from table2 as b 
                 where <condition>);

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