I want to return it as true or false after it is summarized in Group By.

samples table

 id, A, B
1,  1, 1
2,  1, 2
3,  1, 3
4,  1, 3
5,  2, 1

For tables like the ones above,

I would like to write SQL that returns true if B contains 2, or false if not.

Response Example

A,contains
1, true
2, false

How can I write SQL that satisfies the above?