Example 1 3   Subquery

SELECT FirstName, LastName, ZipCode 

FROM customers 

WHERE ZipCode = 

(SELECT ZipCode 

FROM customers 

WHERE FirstName =  Wayne  AND LastName =  John );

Stored procedures and Trigger

A stored procedure is a set of SQL commands that can be compiled and 

stored in the server. If this is done, clients do not have to process the same 

set of SQL commands, but can refer to the stored procedure. 

A trigger is a one or a set of SQL statements, which is invoked automatically 

when a particular event occurs. 

Neither stored procedures nor triggers are supported in MySQL 4.0.

1.2.3  MySQL utilities

MySQL is distributed with a set of support utilities. The Internet however provides 

a quite lager set of third party tools to manage MySQL databases. In this section, 

we attempt to give a brief overview of the MySQL distributed set of supported 

tools. 

Overview of the MySQL server side scripts and utilities

This section introduces the distributed set of server side tools included in the 

MySQL package:

  mysqld

Is the server SQL daemon, which has to run on the server. To use client 

programs, this program must be running, because clients gain access to 

databases by connecting the server.

  mysqld_safe

Is a wrapper script, which adds some more safety features to the SQL 

daemon such as restarting the server when an error occurs, and logging 

run time information.

  mysqld_multi

Is a program for managing multiple MySQL server. This startup script can 

start or stop multiple servers installed on the system.

  mysqld max

Is an extended mysqld server that includes additional features

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MySQL to DB2 UDB Conversion Guide