在 MySQL 中查找重复值 [英] Finding duplicate values in MySQL

问题描述

我有一个带有 varchar 列的表，我想在该列中查找所有具有重复值的记录.我可以用来查找重复项的最佳查询是什么?

I have a table with a varchar column, and I would like to find all the records that have duplicate values in this column. What is the best query I can use to find the duplicates?

推荐答案

使用 GROUP BY 子句执行 SELECT.假设 name 是您要在其中查找重复项的列:

Do a SELECT with a GROUP BY clause. Let's say name is the column you want to find duplicates in:

SELECT name, COUNT(*) c FROM table GROUP BY name HAVING c > 1;

这将返回一个结果，第一列中的 name 值，以及该值在第二列中出现的次数.

This will return a result with the name value in the first column, and a count of how many times that value appears in the second.

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