mysql复杂查询，删除sql

 1、删除mysql中name重复的数据只保留其中id大的一条数据

DELETE t1 FROM 表名 t1
JOIN (
    SELECT name, MAX(id) as max_id
    FROM 表名
    GROUP BY name
) t2 ON t1.name = t2.name AND t1.id <> t2.max_id;

2、查询一个表a和另一个表b   name相同且过滤b表status等于0，a表count大于4并根据count大于倒序

SELECT a.*, b.*
FROM 表1 AS a
JOIN 表2 AS b ON a.name = b.name AND b.status = 0 AND  a.`count`>=4 ORDER BY a.count DESC

3、清空表结构和数据

TRUNCATE TABLE table