repeatable-read.sql

# UPDATE balances SET balance = 500;
UPDATE 2

# start transaction isolation level repeatable read;
START TRANSACTION
# SELECT SUM(balance)
  FROM balances
  WHERE id in ('Alice', 'Bob');
 sum  
------
 1000
(1 row)
                                                   
                                                   SELECT transfer_out('Alice', 400);
                                                   SELECT transfer_out('Bob', 400);
                                                   SELECT * FROM balances;
                                                     id   | balance 
                                                    -------+---------
                                                    Alice |     100
                                                    Bob   |     100
# SELECT *
  FROM balances
  WHERE id in ('Alice', 'Bob');
  id   | balance 
-------+---------
 Alice |     500
 Bob   |     500
(2 rows)

# END;
COMMIT