Question

我有一个包含角色的数据库。由于角色的名称不仅仅使用名称与角色分开。由于存在Female和Select字符，因此我将这些字符保存在不同的表中：

tbl_player，tbl_maleName，tbl_femaleName

在我的MySQL INNER JOIN查询中，我想根据他们的性别选择具有SELECT tbl_player.id, (CASE tbl_player.gender WHEN 'm' THEN tbl_maleName.name WHEN 'f' THEN tbl_femaleName.name END) as gamerName , tbl_player.gender FROM tbl_player INNER JOIN (CASE tbl_player.gender WHEN 'm' THEN tbl_maleName ON tbl_player.gamerName = tbl_maleName.id WHEN 'f' THEN tbl_femaleName ON tbl_player.gamerName = tbl_femaleName.id END)的正确表格。所以像这样：（SQL查询错误，不起作用:(）

ssh <user>@<host>  "cat <filepath>"|pbcopy

提前致谢！

Answer 1

为什么你选择使用2个表来表示我不确定的名字，但我不推荐它。

然而，试试这个：

SELECT
      tbl_player.id
    , (CASE tbl_player.gender WHEN 'm' THEN tbl_maleName.name WHEN 'f' THEN tbl_femaleName.name END) AS gamerName
    , tbl_player.gender
FROM tbl_player
      LEFT JOIN tbl_maleName ON tbl_player.gamerName = tbl_maleName.id
                  AND tbl_player.gender = 'm'
      LEFT JOIN tbl_femaleName ON tbl_player.gamerName = tbl_femaleName.id
                  AND tbl_player.gender = 'f'

Answer 2

您需要使用Union并创建一个值tableOption，其默认值为：

SELECT tbl_player.id FROM tbl_player LEFT JOIN 
(
(SELECT 'male' as tableOption, name FROM tbl_maleName)
UNION
(SELECT 'female' as tableOption, name FROM tbl_femaleName)
) as gamerName 

ON gamerName.this = tbl_player.that
WHERE gamerName.tableOption = 'female'

如果值为女性，则将选择第二个表的值。

MySQL在INNER JOIN中选择INNER JOIN和CASE WHEN

2 个答案: