Hello (this is my 3rd post with sa same content, the others didn't get
in the NG, donno why, so I'm sorry if this message is posted repeatedly)

To be more explicit I will give an example from my current work.

I have three tables, COMPCLASS, COMPMARCA, COMPMODEL.

COMPCLASS
------------
CLASSID CLASS
1 Processor
2 Motherboard

COMPMARCA CLASSNO=FK of CLASSID
--------------
MARCAID CLASSNO MARCA
1 1 AMD
2 1 Intel
3 2 Epox
4 2 Asus
5 2 Gigabyte

COMPMODEL MARCANO=FK of MARCAID
---------------
MODELID MARCANO MODEL
1 1 XP2200+
2 1 Sempron3000+
3 2 Intel P4 2Ghz
4 3 8RDA3I
5 4 K8U-X


There are other tables which relate to the COMPMODEL table on MODELID
field, for example:

ENTRYPROD
------------
EID COMP(notnull) PRICE
1 5 324
2 2 34
4 1 53
etc

COMP field will always have a MODELID corespondent in the COMPMODEL
table, i have some triggers to insure consistency

My usual queries are something like

SELECT ENTRYPROD.*, CLASS, MARCA, MODEL
FROM ENTRYPROD
LEFT JOIN COMPMODEL ON COMP=MODELID
LEFT JOIN COMPMARCA ON MARCANO=MARCAID
LEFT JOIN COMPCLASS ON CLASSNO=CLASSID

This query seems the logical one, but for the sake of testing I was
doing something like

SELECT ENTRYPROD.*, CLASS, MARCA, MODEL
FROM ENTRYPROD
JOIN COMPMODEL ON COMP=MODELID
JOIN COMPMARCA ON MARCANO=MARCAID
JOIN COMPCLASS ON CLASSNO=CLASSID

which return the same amount of records (the actual tables have
thousands of records).
From the test I made, the query execution is fairly the same, however
the JOIN makes faster fetches.

LEFT JOIN (48662 records)
-------------
Prepare time = 0ms
Execute time = 20ms
Avg fetch time = 0.95 ms
Current memory = 2,746,816
Max memory = 2,846,608
Memory buffers = 10,240
Reads from disk to cache = 0
Writes from cache to disk = 0
Fetches from cache = 6,215


JOIN (48662 records)
-------------------
Prepare time = 10ms
Execute time = 10ms
Avg fetch time = 0.48 ms
Current memory = 2,746,476
Max memory = 2,846,608
Memory buffers = 10,240
Reads from disk to cache = 0
Writes from cache to disk = 0
Fetches from cache = 6,215


What is your opinion about these?

I hope I made myself understood

TIA
Radu