Question

我有这个：

1899, 184, 531 *
1900, 184, 531 *
1901, 113, 531
1902, 184, 436

我想要

1899, 184, 531
1901, 113, 531
1902, 184, 436

没有临时表等。如何？

Answer 1

SELECT MIN(Col1), Col2, Col3
FROM yourTable
GROUP BY Col2, Col3

这假设您选择了1899以上的1900记录，因为前者是两者中较小的一个。

如果您想从表中删除重复记录（因为您已将它们定义为重复记录），则可以使用以下查询：

DELETE t1.*
FROM yourTable t1
LEFT JOIN
(
    SELECT MIN(Col1) AS Col1, Col2, Col3
    FROM yourTable
    GROUP BY Col2, Col3
) t2
    ON t1.Col1 = t2.Col1 AND t1.Col2 = t2.Col2 AND t1.Col3 = t2.Col3
WHERE t2.Col1 IS NULL

Answer 2

select min(f1) as f1, f2, f3 from tbl group by f2, f3

Answer 3

如果要在过滤掉重复项的位置进行SELECT，可以使用：

SELECT DISTINCT Col2, Col3 FROM table_name ORDER BY Id;

SQL fiddle for SELECT

或者，如果您想要DELETE查询，可以执行以下操作：

DELETE t1 FROM table_name t1, table_name t2
WHERE t1.Id < t2.Id
AND t1.Col2 = t2.Col2 
AND t1.Col3 = t2.Col3;

SQL fiddle for DELETE

Answer 4

对于DELETE：

DELETE
FROM table1 t
WHERE EXISTS (SELECT u.*
              FROM table1 u
              WHERE u.col2 = t.col2 AND u.col3 = t.col3
              AND u.col1 > t.col1)

当然存在与子查询在同一个表上删除的问题。

Answer 5

DELETE：

DELETE t1
FROM yourtable t1
JOIN yourtable t2
ON t1.col2 = t2.col2
AND t1.col3 = t2.col3
AND t1.col1 > t2.col1

SQLFiddle Demo

Answer 6

这可以删除重复的行。

从table_name中删除column1 in（select column1 from（select column1 from table_name group by column1，column2 having count（*）＆gt; 1）t）;

MySQL，删除重复的行（必须是2列唯一的）

6 个答案:

SQLFiddle Demo