Optimized join - is CONCAT optimized ?

[S F]

Hi all,

Let me explain my case :

i have table 1 with 3 records :
--STATUS--
'somerecord'
'someotherrecord'
'animportantrecord'

and table 2 with 2 records :
--PREFIX-- --MEANING--
'some', 'youre not quite sure"
'anim', 'that one matters'

first i tried to join t1 and t2 like this :
...t1 INNER JOIN t2 ON ( LEFT( STATUS, 4 ) = PREFIX )

but i know that LEFT or any other function on a fields prevents the use of indexes.

I tried another one...

ON STATUS LIKE CONCAT( PREFIX, '%' )

I wonder if that is the best i can find as far as optimization is concerned and would appreciate your help on that issue.

Thanks a lot.

S.