無法從設置的MySQL表中刪除

Question

第一個查詢提供應刪除的一組ID。 第二個查詢嘗試刪除它們。

select abstracts.pmid from abstracts where abstracts.pmid not in 
(select pmid from erpubtbl);

//Fine 555,556,...

delete from abstracts where (pmid) IN (
    select abstracts.pmid from abstracts where abstracts.pmid not in 
    (select pmid from erpubtbl)
);

//You can't specify target table 'abstracts' for update in FROM clause

為什么不能這樣指定目標表？

Answer 1

您不能從table delete並在subquery 引用同一表。

也許這個技巧應該可以幫助您

DELETE FROM abstracts
WHERE  ( pmid ) IN (SELECT *
                    FROM   (SELECT abstracts.pmid
                            FROM   abstracts
                            WHERE  abstracts.pmid NOT IN (SELECT pmid
                                                          FROM   erpubtbl))a);

甚至是Inner Join

DELETE FROM abstracts
USING abstracts
INNER JOIN (SELECT abstracts.pmid
            FROM   abstracts
            WHERE  abstracts.pmid NOT IN (SELECT pmid
                                          FROM   erpubtbl) 
            ) b
         ON abstracts.pmid = b.pmid

Answer 2

在MySQL中執行此操作的一種方法是使用join ：

delete a
    from abstracts a join
         (select a2.pmid
          from abstracts a2
          where a2.pmid not in (select pmid from erpubtbl)
         ) aa
         on a.pmid = aa.pmid;

但是，我認為這很簡單，無需兩次提及abstracts表：

delete a
    from abstracts a left join
         erpubtbl e
         on a.pmid = e.pmid
    where e.pmid is null;

這將刪除abstracts中具有pmid中沒有的erpubtbl -這就是我讀取原始查詢的方式。