如何在两个镜像列中查找 mysql 个重复项

Question

在 MySQL 数据库中我有行。例如：

Varchar1    | Varchar2    
XXXXXXXXXX   YYYYYYYYYY   
YYYYYYYYYY   XXXXXXXXXX 
XXXXXXXXXX   CCCCCCCCCC
YYYYYYYYYY   AAAAAAAAAA
CCCCCCCCCC   AAAAAAAAAA

如何找到（并删除）第 1 行和第 2 行中的重复项？

不应删除一行（1 或 2）。

Answer 1

SELECT t1.id, t1.varchar1,t1.varchar2,t2.id, t2.varchar1,t2.varchar2
from yourtable t1, yourtable t2
where t1.id<>t2.id and t1.varchar1=t2.varchar2

试试这个，如果不行再回来:)

如果这检索到您想要的数据，那么删除就很容易了：

DELETE from yourtable WHERE id in( SELECT t1.id from yourtable t1, yourtable t2
    where t1.id<>t2.id and t1.varchar1=t2.varchar2)

警告：仅当您不在生产环境中或者您确定自己在做什么或者您在事务中时才使用 DELETE（开始...）

Answer 2

已解决。我已将 BIGINT 值与 varchar1 和 varchar2 的散列按位与相加。

ALTER TABLE t1 ADD COLUMN hex1 BIGINT UNSIGNED NOT NULL; ALTER TABLE t1 ADD COLUMN hex2 BIGINT UNSIGNED NOT NULL; ALTER TABLE t1 ADD COLUMN hex BIGINT UNSIGNED NOT NULL; UPDATE t1 SET hex1 = CONV(SUBSTRING(CAST(SHA(varchar1) AS CHAR), 1, 16), 16, 10), hex2 = CONV(SUBSTRING(CAST(SHA(varchar2) AS CHAR), 1, 16), 16, 10), hex = hex1&hex2; ALTER TABLE t1 DROP COLUMN hex1; ALTER TABLE t1 DROP COLUMN hex2;

并按十六进制列分组

SELECT t1.* GROUP BY hex;

如何在两个镜像列中查找 mysql 个重复项

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