Query question - Mailing list pgsql-sql

Hi, 

I am new to the list so feel free to let me know if I am out of line.

My question is:

I have a table that has log events for pieces of equipment.  For each piece of equipment this table may contain 1 or more (hundreds potentially).

I need to write a query that will return only the last 5 log events for each (and every) piece of equipment.

log_table (

equipment_id character(30),

log_date date,

log_time time,

event_desc text

)

Thanks for your help.