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` -- 3. 通过 id not in 删除其他重复数据 DELETE from 表1 where id not in ( -- 2. 获取到要保留的数据id SELECT r.id from ( -- 1. 查询id和筛选字段,通过 GROUP BY 保留一条 SELECT t.id,t.字段1 阅读全文
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SqlServer 关联更新语句: update a set a.pname = b.name from 表a a inner join 表b b on a.pid = b.id MySQL 关联更新语句 UPDATE 表s s LEFT JOIN 表j j ON s.uid = j.id set 阅读全文
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mysql 删除表中多余的重复记录(多个字段),只留有id最小的记录 DELETE FROM 表1 f WHERE (f.字段1,f.字段2) IN ( SELECT 字段1,字段2 FROM 表1 GROUP BY 字段1,字段2 HAVING count(*) > 1 ) AND id NOT 阅读全文
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查询表重复数据: SELECT * FROM 表1 f WHERE (f.字段1,f.字段2) in (SELECT 字段1,字段2 FROM 表1 GROUP BY 字段1,字段2 HAVING count(*)>1); 查询表中多余的重复记录,只留有id最小的记录 select * FROM 表 阅读全文