KDB Q Code for Pivot Table

MacBook-Pro:m32 xbsd$ ./q
KDB+ 3.1 2013.09.05 Copyright (C) 1993-2013 Kx Systems
m32/ 4()core 16384MB xbsd macbook-pro.local 192.168.1.2 PLAY 2013.12.04

q)n:5000000
q)sym:`a`b`c`d`e`f`g`h`i`j`k`l`m`n`o`p`q`r`s`t
q)t:([]col1:n?1000;col2:n?1000; col3:n?1000; grp:n?sym)
q)s:sym

q)\t exec s#(grp!col4) by col1:col1,col2:col2 from update col4:sum col3 by col1,col2,grp from t
11865
q)select[10] from exec s#(grp!col4) by col1:col1,col2:col2 from update col4:sum col3 by col1,col2,grp from t
col1 col2| a   b   c   d   e    f g    h    i    j   k   l   m   n   o   p   ..
---------| ------------------------------------------------------------------..
0    0   |                                           662             977     ..
0    1   |         881     16     313       1544 943     291         623     ..
0    2   |                                                       336         ..
0    3   |         533            674  1637          658                     ..
0    4   |                 1362                          338         178 322 ..
0    5   |         557                 758                   84      936     ..
0    6   |         776 519        1516                       287             ..
0    7   | 906 239                     293                                   ..
0    8   |                 829              19                               ..
0    9   |             663             551                           814     ..
q)