查找MySQL表孔，其中ID是不是唯一

Question

一個MySQL表被定義爲：

CREATE TABLE tbl_misure_30m (
    m_rcd_id   INT NOT NULL AUTO_INCREMENT , 
    m_fon_id   INT UNSIGNED, 
    m_timestamp  TIMESTAMP, 
    m_fon_rcd_id  INT UNSIGNED, 
    m_fon_Leq   FLOAT(4,2), 
    m_fon_LsMax  FLOAT(4,2), 
    m_Leq_state  INT, 
    m_LsMax_state  INT, 
    m_fon_mem_block INT, 

    INDEX fon_key (m_fon_id), 
    FOREIGN KEY (m_fon_id) REFERENCES tbl_users(fon_id) 
    ON DELETE CASCADE 
    ON UPDATE CASCADE, 

    PRIMARY KEY (m_rcd_id) 

) ENGINE = InnoDB; 

其中：

• m_rcd_id是自動增量索引
• m_fon_id是「我的用戶」ID有幾個m_fon_rcd_id
• m_fon_rcd_id是相對於每個m_fon_id的記錄ID（因此它們不是唯一的）。

不幸的是，數據庫設計無法更改。

現在，我需要驗證列m_fon_rcd_id（爲每個m_fon_id）不包含洞（在這種情況下，我需要知道範圍）。

我想要的是一個結果集： gap_starts_at | gap_ends_at | m_fon_id |

我發現this answer但它需要是理所當然的各種ID都是唯一的：

SELECT (t1.m_fon_rcd_id + 1) as gap_starts_at, 
     (SELECT MIN(t3.m_fon_rcd_id) -1 FROM tbl_misure_30m t3 WHERE t3.m_fon_rcd_id > t1.m_fon_rcd_id) as gap_ends_at 
FROM tbl_misure_30m t1 
WHERE NOT EXISTS (SELECT t2.m_fon_rcd_id FROM tbl_misure_30m t2 WHERE t2.m_fon_rcd_id = t1.m_fon_rcd_id + 1) 
HAVING gap_ends_at IS NOT NULL 

有什麼建議？

在此先感謝！

Answer 1

我會通過獲取下一個值來解決這個問題。然後做一些算術上說：

select m_fon_rcd_id + 1 as gapstart, next_m_fon_rcd_id - 1 as gap_ends, 
     (next_m_fon_rcd_id - m_fon_rcd_id - 1) as gap_length 
from (select m_fon_rcd_id, 
      (select m2.m_fon_rcd_id 
       from tbl_misure_30m m2 
       where m2.m_fon_rcd_id > m.m_fon_rcd_id 
       order by m_fon_rcd_id 
       limit 1 
      ) as next_m_fon_rcd_id 
     from tbl_misure_30m m 
    ) m 
where next_m_fon_rcd_id > m_fon_rcd_id + 1; 

編輯：

如果你想內m_fon_id做到這一點的差距，你可以將其添加到查詢的各個部分：

select m_fon_id, m_fon_rcd_id + 1 as gapstart, next_m_fon_rcd_id - 1 as gap_ends, 
     (next_m_fon_rcd_id - m_fon_rcd_id - 1) as gap_length 
from (select m_fon_rcd_id, 
      (select m2.m_fon_rcd_id 
       from tbl_misure_30m m2 
       where m2.m_fon_id = m.m_fon_id and 
        m2.m_fon_rcd_id > m.m_fon_rcd_id 
       order by m_fon_rcd_id 
       limit 1 
      ) as next_m_fon_rcd_id 
     from tbl_misure_30m m 
    ) m 
where next_m_fon_rcd_id > m_fon_rcd_id + 1;