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
我找到了一个简单的方法。(保持最新的)
DELETE t1 FROM table_name t1 INNER JOIN table_name t2
WHERE t1.primary_id < t2.primary_id
AND t1.check_duplicate_col_1 = t2.check_duplicate_col_1
AND t1.check_duplicate_col_2 = t2.check_duplicate_col_2
...
其他回答
简单和快速的所有情况:
CREATE TEMPORARY TABLE IF NOT EXISTS _temp_duplicates AS (SELECT dub.id FROM table_with_duplications dub GROUP BY dub.field_must_be_uniq_1, dub.field_must_be_uniq_2 HAVING COUNT(*) > 1);
DELETE FROM table_with_duplications WHERE id IN (SELECT id FROM _temp_duplicates);
我找到了一个简单的方法。(保持最新的)
DELETE t1 FROM table_name t1 INNER JOIN table_name t2
WHERE t1.primary_id < t2.primary_id
AND t1.check_duplicate_col_1 = t2.check_duplicate_col_1
AND t1.check_duplicate_col_2 = t2.check_duplicate_col_2
...
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
)
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
MySQL对引用要删除的表有限制。你可以用一个临时表来解决这个问题，比如:
create temporary table tmpTable (id int);
insert into tmpTable
(id)
select id
from YourTable yt
where exists
(
select *
from YourTabe yt2
where yt2.title = yt.title
and yt2.company = yt.company
and yt2.site_id = yt.site_id
and yt2.id > yt.id
);
delete
from YourTable
where ID in (select id from tmpTable);
以下是Kostanos在评论中的建议: 上面唯一缓慢的查询是DELETE，适用于数据库非常大的情况。这个查询可以更快:
DELETE FROM YourTable USING YourTable, tmpTable WHERE YourTable.id=tmpTable.id
