index on two fields

[ohitsme]

hey,

 

i have a table like this (for adding categories to different types of content (sites,reviews,galleries)

 

catforitem table:

id (primary key)

catid int

itemit int

type varchar

 

so, if i wanted to see categories for site id #2 it would be

select catid from catforitem where itemid=2 and type="site"

 

if it was for gallery id 23

select catid from catforitem where itemid=23 and type="gallery"

 

you get the idea. basically, the query is always a mix of itemid & type. if i add an index based on both of these fields (as one index), is that the ideal situation? (rather than adding two seperate indexes)

 

if i do, does it matter what way round i query it (ie itemid first then type, or can i do it vice versa and no difference in performace)?

 

thanks

[Mchl]

Yes it would be better to create an index covering both columns, and yes, order of columns does matter.