mysql - 值对应于 MYSQL 中的 NOT AT ALL

Question

MySQL中有三个表，如下所示

Table:Travel             Table:Airline           Table:Location

Code   From   To         Code   Name             Port   Country
-----  ----   ---        ----   ----             ---    -------
ET     PAR    IST        ET     Ettihad          PAR    France
ET     NYC    ANK        VA     VirginAir        MER    France
VA     BER    PAR        TA     TurkishAir       IST    Turkey
TA     SIN    MER        AF     AirFlorida       SIN    Singapore
TA     SHA    SIN        VM     VimanaAir        ANK    Turkey
AF     MER    DUB                                 

我想查找根本不从法国出发的航空公司的名称，其中还包括根本没有任何航类的航空公司。请注意，ET 和 AF 从法国出发。所以，结果表将是

Airline
-------
VirginAir
TurkishAir
VimanaAir

我已经用一般的 LEFT JOIN 查询进行了测试，发现 WHERE Location.Country <> 'France'所有连接消除了 AF 但仍然显示 ET。

表格和数据可供任何人测试:

CREATE TABLE Airline (
  `Code` varchar(2) NOT NULL,
  `Name` varchar(30) NOT NULL,
  PRIMARY KEY (`Code`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO Airline (Code, `Name`) VALUES
('AF', 'AirFlorida'),
('ET', 'Ettihad'),
('TA', 'TurkishAir'),
('VA', 'VirginAir'),
('VM', 'VimanaAir');

CREATE TABLE Location (
  `Port` varchar(3) NOT NULL,
  Country varchar(30) NOT NULL,
  PRIMARY KEY (`Port`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO Location (Port, Country) VALUES
('ANK', 'Turkey'),
('DUB', 'Emirates'),
('IST', 'Turkey'),
('MER', 'France'),
('NYC', 'USA'),
('PAR', 'France'),
('SIN', 'Singapore');

CREATE TABLE Travel (
  `Code` varchar(2) NOT NULL,
  `From` varchar(3) NOT NULL,
  `To` varchar(3) NOT NULL,
  PRIMARY KEY (`Code`,`From`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO Travel (Code, `From`, `To`) VALUES
('AF', 'MER', 'DUB'),
('ET', 'NYC', 'ANK'),
('ET', 'PAR', 'IST'),
('TA', 'SHA', 'SIN'),
('TA', 'SIN', 'MER'),
('VA', 'BER', 'PAR');

Answer 1

尝试:

select *
from Airline a
where not exists(
  select 1
  from Travel t
  join Location l
  on t.from = l.port
  where t.Code = a.code
    and l.Country = 'France'
 )

演示:http://sqlfiddle.com/#!2/0e7dd/1