Performing transactions

Create dummy tables and sample data to understand this recipe:

mysql> CREATE DATABASE bank;
mysql> USE bank;
mysql> CREATE TABLE account(account_number varchar(10) PRIMARY KEY, balance int);
mysql> INSERT INTO account VALUES('A',600),('B',400);

How to do it...

To start a transaction (set of SQLs), execute the START TRANSACTION or BEGIN statement:

mysql> START TRANSACTION;
or 
mysql> BEGIN;

Then execute all the statements that you wish to be inside a transaction, such as transferring 100 from A to B:

mysql> SELECT balance INTO @a.bal FROM account WHERE account_number='A';

Programmatically check if @a.bal is greater than or equal to 100 
mysql>...