Difference between revisions of "AVG"
From SQLZOO
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<p>See also</p> | <p>See also</p> | ||
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| − | <li>[ | + | <li>[[MAX |MAX function]]</li> |
| − | <li>[ | + | <li>[[COUNT |COUNT function]]</li> |
| − | <li>[ | + | <li>[[MIN |MIN function]]</li> |
</ul> | </ul> | ||
Revision as of 12:37, 13 July 2012
| AVG(f) | ||
|---|---|---|
| Engine | OK | Alternative |
| ingres | Yes | |
| mysql | Yes | |
| oracle | Yes | |
| postgres | Yes | |
| sqlserver | Yes | |
AVG
AVG gives the average (the mean) of a whole column or a group of rows for a single column of values.
AVG is an aggregate function it is normally used with GROUP BY.
The mean of the values 2, 5, 5 is (2+5+5)/3 = 12/3 = 4, you divide by 3 because there are 3 numbers in this example.
NULL values do not contribute to the calculation.
SELECT region, AVG(population)
FROM bbc
GROUP BY region
With a GROUP BY region statement each region shows up just once.
The AVG column gives the average population per country for each region.
SELECT region, AVG(population) FROM bbc GROUP BY region
See also
