What indexes to create?

Question

Hey,
I am creating several reports using a table called Employee_School which as approx 2000000 rows and I am wondering what indexes the table should have in order to speed up my selects.
My 'where' clause is using the following columns in my select statement:
NBR_DISTRICT,
DATE_PAY_PERIOD,
SCHOOL_YEAR,
CALENDAR_YEAR,
FISCAL_YEAR,
POSITION,
PAY_TYPE,
CODE
where the user selects a value from a drop down for every column, and 'ALL' can be selected for every column besides the first.
Indexes are kind of new to me so I am not sure what would be needed in this case and with similar situations. Would a separate index be needed for every column, or would I need several multiple column indexes, or would the one multiple column index be enough.
Any suggestions?
Thanks

Answer 1

Hi ,
I have an composite index ( 2 columns ) and I'd to know if the second column is being used ,the where condition are using >= and <= :
desc teste_range:
BEGIN_ACCESS_NBR NOT NULL VARCHAR2(32)
END_ACCESS_NBR NOT NULL VARCHAR2(32)
etc..
select count(*):
COUNT(*)
1585402
my index is begin_access_nbr , end_access_nbr and my select is:
select * from teste_range
WHERE
BEGIN_ACCESS_NBR <= '1162336999' AND
END_ACCESS_NBR >= '1162336999' AND
LENGTH(BEGIN_ACCESS_NBR) = LENGTH('1162336999') AND
LENGTH(END_ACCESS_NBR) = LENGTH('1162336999') AND
( ACCESS_RANGE_EFF_DT <= '20060728' AND
(ACCESS_RANGE_EXPR_DT IS NULL OR ACCESS_RANGE_EXPR_DT > '20060728'));
select count(distinct (BEGIN_ACCESS_NBR)) from teste_range;
1100716
select count(distinct (end_ACCESS_NBR)) from teste_range;
1100551
this select ( or other changing the numbers ) always returned 1 row.
thanks.