ref: a8d00e5d56b261376410c3c87c46327362763bd8
dir: /sys/src/cmd/python/Doc/lib/sqlite3/mysumaggr.py/
import sqlite3 class MySum: def __init__(self): self.count = 0 def step(self, value): self.count += value def finalize(self): return self.count con = sqlite3.connect(":memory:") con.create_aggregate("mysum", 1, MySum) cur = con.cursor() cur.execute("create table test(i)") cur.execute("insert into test(i) values (1)") cur.execute("insert into test(i) values (2)") cur.execute("select mysum(i) from test") print cur.fetchone()[0]