Storing statistical data, do I need DECIMAL, FLOAT or DOUBLE?

Question

I am creating for fun, but I still want to approach it seriously, a site which hosts various tests. With these tests I hope to collect statistical data.

Some of the

Answer 1

Linger: The website you mention and quote has IMO some imprecise info that made me confused. In the docs I read that when you declare a float or a double, the decimal point is in fact NOT included in the number. So it is not the number of chars in a string but all digits used.

Compare the docs: "DOUBLE PRECISION(M,D).. Here, “(M,D)” means than values can be stored with up to M digits in total, of which D digits may be after the decimal point. For example, a column defined as FLOAT(7,4) will look like -999.9999 when displayed" http://dev.mysql.com/doc/refman/5.1/en/floating-point-types.html

Also the nomenclature in misleading - acc to docs: M is 'precision' and D is 'scale', whereas the website takes 'scale' for 'precision'.

Thought it would be useful in case sb like me was trying to get a picture. Correct me if I'm wrong, hope I haven't read some outdated docs:)