DISTINCT clause in SQLite

Question

Recently i found that SQLite don\'t support DISTINCT ON() clause that seems postgresql-specific. For exeample, if i have table t with columns

Answer 1

sqlite> SELECT * FROM t GROUP BY b;
2|5
4|6
(for each b: one (unpredictable) value of a)

sqlite> SELECT * FROM (SELECT * FROM t ORDER BY a DESC) GROUP BY b;
1|5
3|6
(for each b: the row with min a)

sqlite> SELECT * FROM (SELECT * FROM t ORDER BY a ASC) GROUP BY b;
2|5
4|6
(for each b: the row with max a)