At 10:43 +0800 10/4/02, Niclas Hedhman wrote: >If I have a table, > >Name VARCHAR(100) >L DOUBLE >a DOUBLE >b DOUBLE > >and execute the incredible > >SELECT * FROM Colors WHERE >SQRT( > SQ( > ABS( L - 45.5 ) > ) + > SQ( > ABS( a - 13.2 ) > ) + > SQ( > ABS( b + 23.4 ) > ) >) < 2.5 ; > >Could MySQL benefit in any way by indexing the L,a,b fields? Or will it just >plough through all the records one by one, anyway?
It has to read each row in order to evaluate the expression. An index will do you no good. How could it be otherwise? > >Niclas --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
