┌──────────────────────────────────────┐
│SELECT *                                                                    │
│    FROM 親表                                                               │
│    WHERE EXISTS (                                                          │
│        SELECT * FROM (                                                     │
│          SELECT * FROM (                                                   │
│            SELECT * FROM (                                                 │
│              SELECT * FROM (                                               │
│                SELECT * FROM (                                             │
│                  SELECT * FROM (                                           │
│                    SELECT * FROM (                                         │
│                      SELECT * FROM (                                       │
│                          SELECT *                                          │
│                              FROM 子表                                     │
│                              WHERE 子表.列 = 親表.列                       │
│                      ) AS [a]                                              │
│                    ) AS [a]                                                │
│                  ) AS [a]                                                  │
│                ) AS [a]                                                    │
│              ) AS [a]                                                      │
│            ) AS [a]                                                        │
│          ) AS [a]                                                          │
│        ) AS [a]                                                            │
│    );                                                                      │
└──────────────────────────────────────┘
上記のようなのもいける。

親表は、子表が深くても効くようだ。