我的数据库中有一个表story_category,其中包含损坏的条目。下一个查询将返回损坏的条目:

SELECT * 
FROM  story_category 
WHERE category_id NOT IN (
    SELECT DISTINCT category.id 
    FROM category INNER JOIN 
       story_category ON category_id=category.id);

我试图删除它们执行:

DELETE FROM story_category 
WHERE category_id NOT IN (
    SELECT DISTINCT category.id 
    FROM category 
      INNER JOIN story_category ON category_id=category.id);

但我得到了下一个错误:

#1093-不能在FROM子句中为更新指定目标表“story_category”

我如何克服这一问题?


当前回答

最近,我不得不更新同一个表中的记录,如下所示:

UPDATE skills AS s, (SELECT id  FROM skills WHERE type = 'Programming') AS p
SET s.type = 'Development' 
WHERE s.id = p.id;

其他回答

如果Priority列值在表中大于等于1,并且在WHERE子句中使用同一表上的子查询,以确保至少有一行包含Priority=1(因为这是在执行更新时要检查的条件),则我会这样做:


UPDATE My_Table
SET Priority=Priority + 1
WHERE Priority >= 1
AND (SELECT TRUE FROM (SELECT * FROM My_Table WHERE Priority=1 LIMIT 1) as t);

我知道它有点难看,但它确实很好。

试试这个

DELETE FROM story_category 
WHERE category_id NOT IN (
SELECT DISTINCT category.id 
FROM (SELECT * FROM STORY_CATEGORY) sc;

最近,我不得不更新同一个表中的记录,如下所示:

UPDATE skills AS s, (SELECT id  FROM skills WHERE type = 'Programming') AS p
SET s.type = 'Development' 
WHERE s.id = p.id;
DELETE FROM story_category
WHERE category_id NOT IN (
    SELECT cid FROM (
        SELECT DISTINCT category.id AS cid FROM category INNER JOIN story_category ON category_id=category.id
    ) AS c
)

子查询中的内部联接是不必要的。看起来您想要删除story_category中的条目,其中category_id不在类别表中。

而不是:

DELETE FROM story_category 
WHERE category_id NOT IN (
    SELECT DISTINCT category.id 
    FROM category INNER JOIN
         story_category ON category_id=category.id);

执行以下操作:

DELETE FROM story_category 
WHERE category_id NOT IN (
    SELECT DISTINCT category.id 
    FROM category);