刪除mySQL表中的重復項

Question

我正在嘗試編寫我的第一個mySQL查詢。 如果它們具有相同的商品編號字段，則需要刪除它們。 我寫了這個查詢：

    SELECT
    article_number, COUNT(*)
FROM
    article_numbers
GROUP BY
    article_number
HAVING 
    COUNT(*) > 1

它顯示了所有重復的行。 但是，如何刪除每個重復項中除了1之外的所有內容？

謝謝

編輯：

我試過這個查詢：

delete article_numbers from article_numbers inner join 
    (select  article_number
     from article_numbers 
     group by article_number
     having count(1) > 1) as duplicates
   on (duplicates.article_number = article_numbers.article_number)

但這給了我這個錯誤：

無法刪除或更新父行：外鍵約束失敗（ api products ，CONSTRAINT products_article_number_id_foreign FOREIGN KEY（ article_number_id ）參考article_numbers （ id ））

編輯2：

我暫時禁用了外鍵，現在刪除查詢起作用了。 但是，如何修改不刪除重復行之一？

Answer 1

使用CROSS JOIN 。

詢問

delete t1
from article_numbers t1,
article_numbers t2
where t1.id > t2.id 
and t1.article_number = t2.article_number;

小提琴演示

Answer 2

我使用一個相當簡單的查詢來刪除重復項：

;WITH DEDUPE AS (
SELECT ROW_NUMBER() OVER(
    PARTITION BY article_number
        ORDER BY (SELECT 1)) AS RN
FROM article_numbers)
DELETE FROM DEDUPE
WHERE RN != 1

Answer 3

Delete c
from (select *,rank() over(order by article_number) as r  from article_numbers )c
where c.r!=1

Answer 4

如果存在相同的article_number但具有更高的ID，則刪除一行：

delete from article_numbers t1
where exists (select 1 from article_numbers t2
              where t2.article_number = t1.article_number
                and t2.id > t1.id)

核心ANSI SQL，因此我想它可與MySQL和SQL Server一起使用。

Answer 5

我認為這會有所幫助：

    WITH tblTemp as
    (
    SELECT ROW_NUMBER() Over(PARTITION BY Name,Department ORDER BY Name)
       As RowNumber,* FROM <table_name>
    )
    DELETE FROM tblTemp where RowNumber >1

Answer 6

我修改了查詢，並認為現在可以使用：

SET FOREIGN_KEY_CHECKS=0;
delete article_numbers from article_numbers inner join 
    (select  min(id) minid, article_number
     from article_numbers 
     group by article_number
     having count(1) > 1) as duplicates
   on (duplicates.article_number = article_numbers.article_number and duplicates.minid <> article_numbers.id)

但這似乎很復雜。 我將檢查@Ullas方法，以查看它是否也有效。