WINDOW FUNCTION

obclient> CREATE TABLE t1(c1 INT, c2 INT);
Query OK, 0 rows affected 

obclient> INSERT INTO t1 VALUES(1, 1);
Query OK, 1 rows affected 

obclient> INSERT INTO t1 VALUES(2, 2);
Query OK, 1 rows affected 

obclient> INSERT INTO t1 VALUES(3, 3);
Query OK, 1 rows affected 

Q1: 
obclient> EXPLAIN SELECT MAX(c1) OVER(PARTITION BY c1 ORDER BY c2) FROM t1;

Query Plan:
| ========================================
|ID|OPERATOR       |NAME|EST. ROWS|COST|
----------------------------------------
|0 |WINDOW FUNCTION|    |3        |45  |
|1 | SORT          |    |3        |44  |
|2 |  TABLE SCAN   |T1  |3        |37  |
========================================

Outputs & filters: 
-------------------------------------
  0 - output([T_FUN_MAX(T1.C1)]), filter(nil), 
      win_expr(T_FUN_MAX(T1.C1)), partition_by([T1.C1]), order_by([T1.C2, ASC]), window_type(RANGE), upper(UNBOUNDED PRECEDING), lower(CURRENT ROW)
  1 - output([T1.C1], [T1.C2]), filter(nil), sort_keys([T1.C1, ASC], [T1.C2, ASC])
  2 - output([T1.C1], [T1.C2]), filter(nil), 
      access([T1.C1], [T1.C2]), partitions(p0)