带有子查询的 SQL 查询

Question

我需要检索与 6 或 7 号玩家居住在同一街道和城镇的所有玩家的玩家编号、姓名、街道和城镇；

我不知道如何编写 SQL 查询，我想我需要在 WHERE 子句中有一个子查询，但不知道该怎么做。

这是我想出的，但我目前无法测试它

SELECT playerNo, name, street, town
FROM Players
WHERE street IN ( SELECT street, playerNo
                  FROM Players
                  WHERE playerNo IN (6,7));
AND town IN (SELECT town, playerNo
             FROM Players
             WHERE playerNo IN (6,7));

应该兼容Oracle 10g

感谢所有回复的人！

Answer 1

您没有说明您的 DBMS，所以这是 ANSI SQL 解决方案（适用于 Oracle、PostgreSQL、DB2、Teradata、MySQL 以及可能还有很多其他解决方案）：

SELECT playerNo, name, street, town
FROM Players
WHERE (street, town) IN (SELECT street, town
                         FROM Players
                         WHERE playerNo IN (6,7));

关于IN 运算符的旁注：

您的表达式town IN (SELECT town, playerNO ... 无效，因为子选择必须与IN 运算符左侧的列数完全相同。在你的情况下，你必须写town IN (SELECT town FROM ...)

Answer 2

这样的事情应该可以解决问题：

select t.playerNumber, t.name, t.street, t.town
from tablename t
inner join (select street, town from tablename where playerNumber in (6,7)) aux on aux.street = t.street and aux.town = t.town

Answer 3

SELECT p1.playerNo, p1.name, p1.street, p1.town
FROM Players AS p1
INNER JOIN Players AS p2 ON p2.street = p1.street AND p2.town = p1.town
WHERE p2.playerNo IN (6,7)

通常最好避免子查询，因为数据库优化器无法“看到括号内部”。