mysql - 使用 MySQL 在同一个简单 SELECT 中进行不能作为子查询的多个查询，导致生成单个多行结果

Question

我有一个特定的问题，无法通过非常简单的多子查询 SELECT 来解决，如底部所示:采用查询 1

SELECT playername AS Rookie FROM MinecraftMySQL.`lb-players` WHERE onlinetime >= 129600 AND onlinetime < 648000 ORDER BY playername;

返回结果如下

+------------------+
| Rookie           |
+------------------+
| _Golden_Apple    |
| _MineTrick_      |
+------------------+

(只是整个结果的一部分)和查询 2

SELECT playername AS Eager FROM MinecraftMySQL.`lb-players` WHERE onlinetime >= 648000 AND onlinetime < 1296000 ORDER BY playername;

返回类似(只是整个结果的一部分)

+-----------------+
| Eager           |
+-----------------+
| 1Herofox        |
| 1lyndon         |
+-----------------+

这个想法是将这些列组合起来得到如下所示的内容:

+------------------+-----------------+
| Rookie           | Eager           |
+------------------+-----------------+
| _Golden_Apple    | 1Herofox        |
| _MineTrick_      | 1lyndon         |
+------------------+-----------------+

类似的查询

SELECT
    (SELECT playername FROM MinecraftMySQL.`lb-players` WHERE onlinetime >= 129600 AND onlinetime < 648000) AS Rookie,
    (SELECT playername FROM MinecraftMySQL.`lb-players` WHERE onlinetime >= 648000 AND onlinetime < 1296000) AS Eager
;

导致 1242 (21000):子查询返回超过 1 行。谷歌搜索是一个问题，因为我不知道该用什么词；使用过

mysql merge subqueries that return multiple rows
mysql multiple columns in result from subqueries
mysql select multiple queries as columns

只是为了得到一些完全不同的东西。

结果大多仅供人类查看，行与其他列无关，所以用什么手段来合并这些列并不重要，只要性能不下降太多即可；鉴于它们根本不相关，使得 JOIN 看起来像是错误的工具。

这就是我的理解停止的地方。

Answer 1

您正在寻找UNION:

SELECT playername, 'Rookie' as Rank
  FROM MinecraftMySQL.`lb-players`
  WHERE onlinetime >= 129600 AND onlinetime < 648000
UNION
SELECT playername, 'Eager' as Rank
  FROM MinecraftMySQL.`lb-players`
  WHERE onlinetime >= 648000 AND onlinetime < 1296000
ORDER BY playername;