Force mysql to use index a certain way -

Force mysql to use index a certain way -

i've found when running queries against our mysql db (5.5.27) when optimizer chooses utilize use index range responds quickly, when chooses ref_or_null takes longer.

is there way forcefulness index utilize range?

if you're sure optimizer not using indexes properly, can seek utilize index hints.

select * table1 utilize index (col1_index,col2_index) col1=1 , col2=2 , col3=3;

documentation

mysql