Select ALL rows with WHERE statement

[Alvaro Cobo]

Hi all: 

I've searched into the MySQL manual but I can't find the solution to this very 
silly question. 

I have a select query where I need to filter the data using the WHERE 
statement. But also need to have an option to show all the data in the table. 

For example (something like...): 

SELECT * FROM `tbl_table1`  WHERE field1 = 'Test' #To show all the rows where 
field 1= 'Test'

But also have the choice to select all the rows using something like: 

SELECT * FROM `tbl_table1`  WHERE field1 = * or ALL or %  #Select all the 
fields.

Very thankful in advance. 

Alvaro

PD: System Details: Mysql server version 4.1.11, PHP 4.3.10-2, Debian Sarge.