# Multiply sets

Multiply across a result set.

```
DROP TABLE interest
```

```
CREATE TABLE interest(
yr INTEGER,
rate DECIMAL );
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