Question

Can you write a SQL command for helping me in these two columns?

for example…..these two columns

a1             a2
______       ______
1              1
2              1
1              2
2              3
3              1
3              2
4              1
4              2

I want the output:

a1 a1
1  2
2  3
3  2
4  2

Answer 1

I’m guessing, based on your example, that you want the second column to be the maximum a2 value for the corresponding a1 value.

Then you want:

SELECT a1, MAX(a2) AS a2 FROM table GROUP BY a1