Making SELECT Query faster

Question

I've got a query in MySQL:

SELECT FIELD1, FIELD2, FIELD3 
FROM TABLE1 
WHERE 
  (FIELD3 >= INT1 AND FIELD3 <= INT2) 
  AND FIELD2 IN (INTEGER_LIST)

Any ideas how to make this query faster? Both FIELD2 and FIELD3 are indexed. Even, when check on FIELD2 is removed, nothing happens related to performance.

Execution plan information:

id: 1
select_type: SIMPLE
table: TABLE1
type: ref
possible_keys: FIELD2, FIELD3
key: FIELD2
ref: const
rows: 310000
Extra: using where

Answer 1

Yes. An index on table1(field2, field3, field1) should speed this query:

create index table1_field2_field3_field1 on table1(field2, field3, field1)

Answer 2

Did you try setting up a compound index on (FIELD3, FIELD2) ? (see leftmost prefix issues in MySQL)

Setting an index really depends on the type of query you are expecting :

• possibly on both fields - separately (FIELD2 or FIELD3)
• always on these two fields together and in that order
• can be on (FIELD3. FIELD2) or (FIELD2, FIELD3)