sql的distinct有哪些替代方法

1. 使用GROUP BY语句来实现去重功能：

SELECT column1, column2 FROM table_name GROUP BY column1, column2; 

2. 使用子查询来实现去重功能：

SELECT column1, column2 FROM table_name WHERE (column1, column2) IN (     SELECT DISTINCT column1, column2     FROM table_name ); 

3. 使用窗口函数来实现去重功能：

SELECT DISTINCT column1, column2 FROM (     SELECT column1, column2, ROW_NUMBER() OVER (PARTITION BY column1, column2 ORDER BY column1) AS rn     FROM table_name ) AS subquery WHERE rn = 1;