Created
August 8, 2013 09:23
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mysql 将一个表的重复数据合并
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| -- 临时表 t_temp_a，有重复articleid的记录 | |
| CREATE TEMPORARY TABLE t_temp_a ( | |
| SELECT d.id, d.articleid, d.hitcount, d.cnt | |
| FROM ( | |
| SELECT c.id, c.articleid, c.hitcount, b.cnt | |
| FROM t_article_hitcount AS c | |
| INNER JOIN ( | |
| SELECT articleid, cnt | |
| FROM ( | |
| SELECT articleid, COUNT(*) AS cnt | |
| FROM t_article_hitcount | |
| GROUP BY articleid | |
| ) AS a | |
| WHERE cnt >= 2 | |
| ) AS b ON b.articleid = c.articleid | |
| ) d | |
| ORDER BY d.articleid ASC | |
| ); | |
| -- 将 重复articleid 的记录的 hitcount 合并 | |
| UPDATE t_article_hitcount AS a | |
| INNER JOIN ( | |
| SELECT id, articleid, SUM(hitcount) AS hitcount, cnt | |
| FROM t_temp_a | |
| GROUP BY articleid | |
| ) AS b ON a.articleid = b.articleid | |
| SET a.hitcount = b.hitcount; | |
| -- 对于重复数据，保留且仅保留一条 | |
| DELETE | |
| FROM t_article_hitcount | |
| WHERE id IN ( | |
| SELECT id | |
| FROM t_temp_a | |
| ) AND id NOT IN ( | |
| SELECT MIN(id) | |
| FROM t_temp_a | |
| GROUP BY articleid | |
| ); |
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