表中出現重復數據，需要刪除重復數據，只保留一條

DELETE 
FROM
    crm_participant 
WHERE
    id IN (

SELECT
    c.id cid 
FROM
    crm_participant c 
WHERE
    c.parentPhone IN ( SELECT a.parentPhone FROM crm_participant a GROUP BY a.parentPhone HAVING count( a.parentPhone ) > 1 ) 
    AND c.id NOT IN ( SELECT min( b.id ) FROM crm_participant b GROUP BY b.parentPhone HAVING count( b.parentPhone ) > 1 ) 
ORDER BY
 

    c.parentPhone 

    )


錯誤信息：

> 1093 - You can‘t specify target table ‘crm_participant‘ for update in FROM clause
> 時間: 0.005s

問題分細：
       mysql不允許對同一個表中查出來的數據作為條件，在執行跟新操作。 在一條 sql 語句中不能先查出來部分內容，再同時又對當前表作修改。
       

解決辦法：這個是正確的sql,其實就是對上邊的紅色部分的查詢sql進行了一層包裹。讓查詢出來的信息被一個  select 包裹一下，然後作為條件就可以了
 

DELETE 
FROM
    crm_participant 
WHERE
    id IN (
SELECT
    v.cid 
FROM
    (
SELECT
    c.id cid 
FROM
    crm_participant c 
WHERE
    c.parentPhone IN ( SELECT a.parentPhone FROM crm_participant a GROUP BY a.parentPhone HAVING count( a.parentPhone ) > 1 ) 
    AND c.id NOT IN ( SELECT min( b.id ) FROM crm_participant b GROUP BY b.parentPhone HAVING count( b.parentPhone ) > 1
 
 ) 
ORDER BY
    c.parentPhone 
    ) v 
     )

mysql修改刪除You can't specify target table for update in FROM clause的問題