How to use GROUPBY to find out the minimum value of the specified sorting group-php Tutorial

How to use GROUPBY to find the table structure with the smallest value in the specified sorting group is as follows:
--------------------------------------------------
A1 A2
China 99
China 94
95 in China
US 88
US 70
US 94
UK 79
UK 92
.........

The query results must be grouped by A1 in the specified order, such as (USA, China, UK)
Calculate A2 with the smallest value in the group.

The result is as follows ----------------------
A1 A2
US 70
China 94
UK 79

Reply to discussion (solution)

SELECT A1, MIN (A2) AS A2 FROM test group by A1 order by find_in_set (A1, 'USA, China, UK ');