条件查询

Question

对这个问题有点麻烦： 使用下面的两个表，创建一个子查询或连接语句，在Player_PROFILE表中显示所有由Fisher执行的球员的球员，球队和否。

我提出了以下SQL代码，但我不确定如何完成它或者它是否正确：

SELECT PLAYER_PROFILE.Player, PLAYER_PROFILE.Team,
PLAYER_PROFILE.No
FROM PLAYER_PROFILE
INNER JOIN PLAYER_DETAIL
ON......

Answer 1

不是这个 - 或者我在你的问题中遗漏了什么

SELECT PLAYER_PROFILE.Player, PLAYER_PROFILE.Team, PLAYER_PROFILE.No
FROM PLAYER_PROFILE
INNER JOIN PLAYER_DETAIL ON PLAYER_PROFILE.Player=PLAYER_DETAIL.Player
WHERE PLAYER_DETAIL.Coach = 'Fisher';

Answer 2

SELECT PLAYER_PROFILE.Player, PLAYER_PROFILE.Team,
PLAYER_PROFILE.No
FROM PLAYER_PROFILE
INNER JOIN PLAYER_DETAIL
ON PLAYER_PROFILE.Player = PLAYER_DETAIL.Player
WHERE PLAYER_DETAIL.Coach = "Fisher"

你对玩家名称进行内部联接（http://www.w3schools.com/sql/sql_join_inner.asp），因为你需要一些对每个玩家来说都是唯一的数据...通常这是某种ID（数字/ guid）但是在在你的数据的情况下，它是玩家的名字。

Answer 3

由于两个表只有Player作为公共字段，因此查询将为：

SELECT PLAYER_PROFILE.Player, PLAYER_PROFILE.Team,
PLAYER_PROFILE.No
FROM PLAYER_PROFILE
INNER JOIN PLAYER_DETAIL
ON PLAYER_PROFILE.Player = PLAYER_DETAIL.Player
WHERE PLAYER_DETAIL.Coach = 'Fisher'

说明：上述查询会根据PLAYER名称加入两个表的结果，并会过滤Coach Fisher

的结果

如果您可以更改表格结构，那么我建议您在两个表格中都有PLAERY_ID字段，以便唯一标识播放器而不是Player列。

Answer 4

SELECT
`PLAYER_PROFILE`.`Player`,
`PLAYER_PROFILE`.`Team`,
`PLAYER_PROFILE`.`No`
FROM
`PLAYER_PROFILE`
INNER JOIN
`PLAYER_DETAIL`
ON
`PLAYER_DETAIL`.`Player`=`PLAYER_PROFILE`.`Player`
WHERE
`PLAYER_DETAIL`.`Coach`="Fisher";

不同的玩家可以拥有相同的名称，因此最好为每个玩家使用唯一的ID并加入这些值。