mysql 写一个数据去重,删除重复数据的sql

可以使用以下语句删除重复数据：

DELETE FROM table_name 
WHERE column_name1 IN (SELECT column_name1 
                       FROM (SELECT column_name1, COUNT(*) 
                             FROM table_name 
                             GROUP BY column_name1 
                             HAVING COUNT(*) > 1) 
                       AS t) 
AND column_name2 IN (SELECT column_name2 
                     FROM (SELECT column_name2, COUNT(*) 
                           FROM table_name 
                           GROUP BY column_name2 
                           HAVING COUNT(*) > 1) 
                     AS t);

其中，table_name 是要去重的表名，column_name1 和 column_name2 是需要去重的列名。这个语句会删除所有 column_name1 和 column_name2 都相同的重复数据。