如何选择两列组合相同的行

本文介绍了如何选择两列组合相同的行的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

标题似乎在描述我的问题上做得很差；让我尝试用一​​个简化的例子来解释它：

The title seems to do a really poor job at describing my problem; let me try and explain it with a simplified example:

我说我有下表：

_______________________ |id|variant_id|attr_id| |__|__________|_______| |1 |15 |110 | |2 |15 |110 | |3 |20 |152 | |4 |20 |110 | |5 |21 |110 | |__|__________|_______|

现在，我想要的是一个查询，该查询选择所有行，其中 variant_id 和 attr_id 列出现多次。基本上在此示例中，它应该选择第1行和第2行，因为它们在 variant_id 和 attr_id 的组合中多次出现

Now, what I'd like to have is a query that selects all rows where a combination of the variant_id and attr_id columns occurs more than once. Basically in this example it should select row 1 and 2, because their combination of variant_id and attr_id occurs more than once in the table.

有可能吗？

推荐答案

尝试此查询

SELECT a.* FROM tbl a inner join tbl b ON a.variant_id =b.variant_id AND a.attr_id = b.attr_id WHERE a.id <> b.id;

希望这会有所帮助