Column comparison SQL and Python -


i need compare 2 columns sqllite database (.db) , if found coincidence modify third column. i.e. :

 b c  ------- 11 1  f 21 3  f 54 21 v 65 4  f 96 9  f 82 5  f 71 11 v 53 5  f

if number of column "b" found in column "a" result in column "c" "v".

column "c" set f rows default before start comparison. i'm using python 2.7 , sqllite 3 don't know how kind of comparison.

update mytable      set c = 'v'  b in (select mytable)

here complete python program show works:

# __future__ import print_function # uncomment import python 2.7 import sqlite3  connection = sqlite3.connect(':memory:') cursor = connection.cursor() cursor.execute('create table mytable (a integer, b integer, c text)')  initial_ab_vals = [(11, 1), (21, 3), (54, 21), (65, 4), (96, 9), (82, 5), (71, 11), (53, 5)] cursor.executemany("insert mytable(a, b, c) values (?, ?, 'f')", initial_ab_vals)  print('before update') row in cursor.execute('select * mytable'):     print('    {:2d} {:2d} {}'.format(*row))  cursor.execute("update mytable set c = 'v' b in (select mytable)")   print() print('after update') row in cursor.execute('select * mytable'):     print('    {:2d} {:2d} {}'.format(*row))   connection.commit() connection.close()

output

before update     11  1 f     21  3 f     54 21 f     65  4 f     96  9 f     82  5 f     71 11 f     53  5 f  after update     11  1 f     21  3 f     54 21 v     65  4 f     96  9 f     82  5 f     71 11 v     53  5 f

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