mirror of
https://github.com/mamedev/mame.git
synced 2024-11-16 07:48:32 +01:00
35 lines
934 B
Lua
35 lines
934 B
Lua
|
|
local sqlite3 = require("lsqlite3")
|
|
|
|
local db = sqlite3.open_memory()
|
|
|
|
assert( db:exec "CREATE TABLE test (col1, col2)" )
|
|
assert( db:exec "INSERT INTO test VALUES (1, 2)" )
|
|
assert( db:exec "INSERT INTO test VALUES (2, 4)" )
|
|
assert( db:exec "INSERT INTO test VALUES (3, 6)" )
|
|
assert( db:exec "INSERT INTO test VALUES (4, 8)" )
|
|
assert( db:exec "INSERT INTO test VALUES (5, 10)" )
|
|
|
|
do
|
|
|
|
local square_error_sum = 0
|
|
|
|
local function step(ctx, a, b)
|
|
local error = a - b
|
|
local square_error = error * error
|
|
square_error_sum = square_error_sum + square_error
|
|
end
|
|
|
|
local function final(ctx)
|
|
ctx:result_number( square_error_sum / ctx:aggregate_count() )
|
|
end
|
|
|
|
assert( db:create_aggregate("my_stats", 2, step, final) )
|
|
|
|
end
|
|
|
|
--for a,b in db:urows("SELECT col1, col2 FROM test")
|
|
--do print("a b: ", a, b) end
|
|
|
|
for my_stats in db:urows("SELECT my_stats(col1, col2) FROM test")
|
|
do print("my_stats:", my_stats) end
|