Question

I have a table as below:

id             value
-------------------------
1               1
5               1
7               1
8               4

I can’t get to table as below:

id             value
-------------------------
1               1
8               4

The SQL is

select id,value from table_1 group by id_a

Answer 1

All you have here is a simple MIN() aggregate.

SELECT MIN(id), value AS id FROM table_1 GROUP BY value