mysql-true时查询并不总是显示结果

Question

I am running the following query in mysql and depending on what value has been added will depend if the system displays a row when I run the query. Each row as a value and this should not be a problem and all values that her in the database should display a row but this is not the case, here is my query.

If I enter golf the correct row will show but not for football.

CREATE TABLE `sports` (
  `sport_ID` int(11) NOT NULL,
  `Name` varchar(20) NOT NULL,
  `Tag` varchar(100) NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=latin1;

INSERT INTO `sports` (`sport_ID`, `Name`, `Tag`) VALUES
(1, 'Football', 'Rugby'),
(2, 'Rugby', 'Basketball'),
(3, 'Basketball', 'Golf'),
(4, 'Golf', 'Football')


SELECT *
FROM sports b 
join sports a
on a.Tag = b.Name
where b.sport_ID > a.sport_ID and a.Tag = 'Football'
LIMIT 1

Answer 1

Replace > by <> :

SELECT *
FROM sports b 
left join sports a
on a.Tag = b.Name
where b.sport_ID <> a.sport_ID and a.Tag = 'golf'
LIMIT 1

It returns a row now both for golf and football .

BUT

I suspect that your problem might be more complex than that, perhaps the sample is too small.