Multiply sets
Multiply across a result set.
DROP TABLE interest
CREATE TABLE interest(
yr INTEGER,
rate INTEGER );
INSERT INTO interest VALUES (2002,0.05);
INSERT INTO interest VALUES (2003,0.04);
INSERT INTO interest VALUES (2004,0.05);
INSERT INTO interest VALUES (2005,0.03);
In this example we are attempting to see how much money has been obtained over 4 years due to interest. As the added up rate is not accurate 5 + 4 + 5 + 3 = 17% We need to instead find the logarithm of the compound interest and then we need to sum that. SELECT SUM(LN(1+rate/100)) FROM interest Then we inverse or take the exponent of the logarithm with SELECT EXP(SUM(LN(1+rate/100))) FROM interest and then finally to get the amount after 4 years we times this amount by 100 ($100).
SELECT EXP(SUM(LN(1+rate/100)))*100
FROM interest
Hack 10 Converting subqueries into joins
Hack 11 Converting aggregate subqueries into joins
Hack 16 Search for a String across columns
Hack 24 Multiply Across a Result Set
Hack 25.5 Splitting and combining columns
Hack 26 Include the rows your JOIN forgot
Hack 30 Calculate the maximum/minimum of two fields
Hack 33 Get values and subtotals in one shot
Hack 50 Combine tables containing different data
Hack 51/52 Display rows as columns
Hack 55 Import Someone Else's Data
Hack 62 Issue Queries Without Using a Table
Hack 63 Generate rows without tables
Hack 72 Extract a subset of the results
Hack 78 Break it down by Range
Hack 88 Test two values from a subquery