在MySQL中，可以使用多种方式来查重。下面我列举了几种常用的方法：

1. 使用DISTINCT关键字

```sql

SELECT DISTINCT column_name FROM table_name;

上述语句将返回指定列名中不重复的值。

2. 使用GROUP BY语句

```sql

SELECT column_name FROM table_name GROUP BY column_name HAVING COUNT(column_name) > 1;

上述语句将返回指定列名中出现次数大于1的重复值。

3. 使用子查询

```sql

SELECT column_name FROM table_name WHERE column_name IN (SELECT column_name FROM table_name GROUP BY column_name HAVING COUNT(column_name) > 1);

上述语句将返回指定列名中出现次数大于1的重复值。

4. 使用INNER JOIN语句

```sql

SELECT t1.column_name FROM table_name AS t1 INNER JOIN (SELECT column_name FROM table_name GROUP BY column_name HAVING COUNT(column_name) > 1) AS t2 ON t1.column_name = t2.column_name;

上述语句将返回指定列名中出现次数大于1的重复值。

以上是一些常用的查重方法，你可以根据具体情况选择合适的方法来查询重复数据。