根据特定列的最高值对数据进行分组

Question

 I have two tables department and category.In my query result listing same department multiple times.I want to group departments based on category table priority column.

 Eg Data:

 id    dept_name     dept_category  priority

 1      Cardio         category 2     2
 2      Ortho          category 3     3
 3      Ortho          category 1     1
 4      ENT            category 1     1
 5      Ortho          category 2     2

I wannt the reslt like:

 id    dept_name     dept_category  priority

 1      Cardio         category 2     2
 3      Ortho          category 1     1
 4      ENT            category 1     1

如何获取这样的结果。在我的类别表中，优先级为 1、2、3，然后 1 为最高优先级。我需要根据最高优先级对部门进行分组。

Answer 1

我们可以在 Postgres 中使用DISTINCT ON：

SELECT DISTINCT ON (dept_name) *
FROM yourTable
ORDER BY dept_name, priority;