MySQL 32 - FLOAT and DOUBLE Data Types
FLOAT and DOUBLE data types are data types that can be used to store numbers that can include decimal numbers. They are specifically used to store estimates. What do I mean? I mean that the precision of a FLOAT or DOUBLE value can be lost when doing math. The data types are only capable of maintaining a certain level of precision. The level of precision is usually adequate for most mathematical operations. If you need to store exact data, you will want to look into using the INT or DECIMAL data type instead. The numbers stored in a FLOAT or DOUBLE column are called floating point numbers, we'll see why in just a moment. Why are they called floating point numbers? let's look at a number. 150. This number could be represented as 150, or it could be represented as 1.5 * 10^2, or 1.5e2. With floating point numbers, scientific notation is used. These numbers are called floating point numbers because the decimal can float to different spots as we change the exponent. This means that the data type needs to store the number, how many decimal the number needs moved, and a sign bit. The benefit of floating point numbers is that they allow us to store pretty huge numbers. The down side is that they are not storing values exactly because they are limited in size. This means that only a certain level of precision is to be expected from a floating point data type. If you remember from the video of DECIMAL, precision is the number of digits in a number. As long as the precision for one of these data types exceeds the need for your specific data, the data type can work fine. For example, if you are storing a number like 15 trillion, you don't have to worry as much with precision as your number does not contain a lot of digits. This number can be represented as 1.5 x 10^13. This is a lot different than trying to store 1.5534534534 x10^13. Now we know both of these data types do not maintain a high number of digits correctly, but what is the difference between FLOAT and DOUBLE. The difference is the amount of storage they take up. Float takes up 4 bytes while DOUBLE takes up 8. The benefit in DOUBLE is that because it has more room to store data, it has a higher level of precision and can store bigger numbers. Now, what level of precision can you expect from either of these? FLOAT around 7 and DOUBLE around 15. Now, these data types are obnoxious because the exact values depend on your operating system and in general these monsters cannot be trusted. Especially when you start doing math with different numbers. In general, it is recommended to use the DOUBLE data type to have a higher level of precision and calculations in MySQL are done with DOUBLE. Always remember… prepare for trouble, make it double. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! www.patreon.com/calebcurry Subscribe to my newsletter: eepurl.com/-8qtH Donate!: bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: CalebCurry.com Facebook: www.facebook.com/CalebTheVideoMaker Google+: plus.google.com/+CalebTheVideoMaker2 Twitter: twitter.com/calebCurry Amazing Web Hosting - www.dreamhost.com/r.cgi?1487063 (The best web hosting for a cheap price!)
