MySQL试去重语句测试

版权声明：本文为博主书香代码原创文章，未经博主允许不得转载。 https://blog.csdn.net/u010138825/article/details/83244802

MySQL试去重语句测试

having使用学习

不好意思，将count(*)换为count(id),使用不能偷懒

DELETE FROM wbxx 
WHERE id not in
(
		SELECT id FROM (
				SELECT id FROM wbxx GROUP BY namex HAVING count(id) = 1
				UNION
				SELECT min(id) FROM wbxx GROUP BY namex HAVING count(id) > 1
		) AS temptable1
)