# Difference between revisions of "Multiply sets"

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</source> | </source> | ||

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− | In this example we are attempting to see how much money has been obtained over 4 | + | <p>In this example we are attempting to see how much money has been obtained over 4 |

− | years due to interest. | + | years due to interest.</p> |

− | As the added up rate is not accurate 5 + 4 + 5 + 3 = 17% | + | <p>As the added up rate is not accurate 5 + 4 + 5 + 3 = 17%</p> |

− | We need to instead find the logarithm of the compound interest and then we need to sum that. | + | <p>We need to instead find the logarithm of the compound interest and then we need to sum that.</p> |

− | SELECT SUM(LN((rate/100)+1)) FROM interest | + | <p>SELECT SUM(LN((rate/100)+1)) FROM interest</p> |

− | Then we inverse or take the exponent of the logarithm with | + | <p>Then we inverse or take the exponent of the logarithm with</p> |

− | SELECT EXP(SUM(LN((rate/100)+1))) FROM interest | + | <p>SELECT EXP(SUM(LN((rate/100)+1))) FROM interest</p> |

− | and then finally to get the amount after 4 years we times this amount by 100 ($100). | + | <p>and then finally to get the amount after 4 years we times this amount by 100 ($100).</p> |

</div> | </div> | ||

<source lang='sql' class='def'>SELECT EXP(SUM(LN((rate/100)+1)))*100 | <source lang='sql' class='def'>SELECT EXP(SUM(LN((rate/100)+1)))*100 |

## Revision as of 11:59, 30 July 2012

Multiply across a result set.

```
DROP TABLE interest
```

```
CREATE TABLE interest(
yr INTEGER,
rate INTEGER );
INSERT INTO interest VALUES (2002,5);
INSERT INTO interest VALUES (2003,4);
INSERT INTO interest VALUES (2004,5);
INSERT INTO interest VALUES (2005,3);
```

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((rate/100)+1)) FROM interest

Then we inverse or take the exponent of the logarithm with

SELECT EXP(SUM(LN((rate/100)+1))) FROM interest

and then finally to get the amount after 4 years we times this amount by 100 ($100).

```
SELECT EXP(SUM(LN((rate/100)+1)))*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