我有一个表与以下字段:

id (Unique)
url (Unique)
title
company
site_id

现在,我需要删除具有相同标题、company和site_id的行。一种方法是使用下面的SQL和脚本(PHP):

SELECT title, site_id, location, id, count( * ) 
FROM jobs
GROUP BY site_id, company, title, location
HAVING count( * ) >1

运行此查询后,可以使用服务器端脚本删除重复项。

但是,我想知道这是否只能使用SQL查询。


当前回答

我想更具体地说明我删除了哪些记录,下面是我的解决方案:

delete
from jobs c1
where not c1.location = 'Paris'
and  c1.site_id > 64218
and exists 
(  
select * from jobs c2 
where c2.site_id = c1.site_id
and   c2.company = c1.company
and   c2.location = c1.location
and   c2.title = c1.title
and   c2.site_id > 63412
and   c2.site_id < 64219
)

其他回答

这个解决方案将把重复的数据移到一个表中,唯一的数据移到另一个表中。

-- speed up creating uniques table if dealing with many rows
CREATE INDEX temp_idx ON jobs(site_id, company, title, location);

-- create the table with unique rows
INSERT jobs_uniques SELECT * FROM
    (
    SELECT * 
    FROM jobs
    GROUP BY site_id, company, title, location
    HAVING count(1) > 1
    UNION
    SELECT *
    FROM jobs
    GROUP BY site_id, company, title, location
    HAVING count(1) = 1
) x

-- create the table with duplicate rows
INSERT jobs_dupes 
SELECT * 
FROM jobs
WHERE id NOT IN
(SELECT id FROM jobs_uniques)

-- confirm the difference between uniques and dupes tables
SELECT COUNT(1)
AS jobs, 
(SELECT COUNT(1) FROM jobs_dupes) + (SELECT COUNT(1) FROM jobs_uniques)
AS sum
FROM jobs

删除表中重复的记录。

delete from job s 
where rowid < any 
(select rowid from job k 
where s.site_id = k.site_id and 
s.title = k.title and 
s.company = k.company);

or

delete from job s 
where rowid not in 
(select max(rowid) from job k 
where s.site_id = k.site_id and
s.title = k.title and 
s.company = k.company);

我有这个查询片段的SQLServer,但我认为它可以用在其他DBMS与小的变化:

DELETE
FROM Table
WHERE Table.idTable IN  (  
    SELECT MAX(idTable)
    FROM idTable
    GROUP BY field1, field2, field3
    HAVING COUNT(*) > 1)

我忘了告诉您,这个查询不会删除重复行中id最低的行。如果这对你有用,试试这个查询:

DELETE
FROM jobs
WHERE jobs.id IN  (  
    SELECT MAX(id)
    FROM jobs
    GROUP BY site_id, company, title, location
    HAVING COUNT(*) > 1)

我一直在访问这个页面,任何时候我谷歌“从mysql中删除重复”,但对于我的忽略解决方案不起作用,因为我有一个InnoDB mysql表

这段代码在任何时候都能更好地工作

CREATE TABLE tableToclean_temp LIKE tableToclean;
ALTER TABLE tableToclean_temp ADD UNIQUE INDEX (fontsinuse_id);
INSERT IGNORE INTO tableToclean_temp SELECT * FROM tableToclean;
DROP TABLE tableToclean;
RENAME TABLE tableToclean_temp TO tableToclean;

tableToclean =需要清理的表的名称

tableToclean_temp =创建和删除的临时表

为了复制具有唯一列的记录,例如COL1,COL2, COL3不应该被复制(假设我们在表结构中遗漏了3个唯一列,并且在表中添加了多个重复项)

DROP TABLE TABLE_NAME_copy;
CREATE TABLE TABLE_NAME_copy LIKE TABLE_NAME;
INSERT INTO TABLE_NAME_copy
SELECT * FROM TABLE_NAME
GROUP BY COLUMN1, COLUMN2, COLUMN3; 
DROP TABLE TABLE_NAME;
ALTER TABLE TABLE_NAME_copy RENAME TO TABLE_NAME;

希望将有助于开发。