, a . тАФ :
for a1, b in t1:
for a2, c in t2:
if a1 == a2:
t3.append((a1, b, c))
. a. -:
for row in t1:
t1_map[row[0]] = row
LEFT. , , . тАФ (a, b, c), тАФ (a, b, NULL).
for a, b in t1_map.items():
if a in t2_map:
t3.append((a, b, t2[a]))
else:
t3.append((a, b, 'NULL'))
RIGHT .
FULL , , :
for a, c in t2_map.items():
if a not in t1_map:
t3.append((a, 'NULL', c))
a , hash-map , a. Python itertools.product.
, a , тАФ N x N. , . , .