如何在Mysql中删除相同的值

Question

我想在主题字段中删除相同的值并保留第一行值。

，例如

no topic 

1  1234 

2  1234 

3  1234

no = autoincrement

输出

no topic

1  1234

这是我的代码

$sql ="DELETE FROM data
WHERE no IN (SELECT * 
             FROM (SELECT no FROM data
                   GROUP BY topic HAVING (COUNT(*) > 1)
                  ) AS A
             )";

此代码删除第一个值，但我想删除所有相同的值并保留第一个值，例如。

Answer 1

试试这个

@Configuration
public class MyApplicationContext {
    @Bean
    public DirectoryScanner scanner() {
        return new WatchServiceDirectoryScanner("/tmp/myDir");
    }
}

@Component
public class MyApplicationContext {
    @Bean
    public DirectoryScanner scanner() {
        return new WatchServiceDirectoryScanner("/tmp/myDir");
    }
}

sqlfiddle