Date Arithmetic With MySQL (
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When dealing with date and time values, one of the more common (and complex) tasks involves performing addition and subtraction operations on these values. However, with MySQL's powerful date and time API taking care of all the minor adjustments for you, manipulating date and time data is no longer the tedious and time-consuming process it used to be. Find out why, inside.
If you're familiar with MySQL, one of the planet's most popular open-source
RDBMS, you already know that it supports a wide variety of data types for
numbers, strings and dates. These data types perform two very
important
functions: they enforce consistency on the data in a MySQL table
(ensuring, for example, that numeric columns do not contain character data) and
they optimize the space (bytes) required to store each type of data.
Now, MySQL comes with almost different data types, including types for
integers, floating-point numbers, strings, date and time values, and data
collections. One of the larger categories among these is the one containing date
and time types, primarily because MySQL includes date and time types to meet
almost every need you could think of. For example, there's the TIMESTAMP type to
store timestamps, the DATE and TIME types to store just dates or times, the
hybrid DATETIME type to store both, and the YEAR type to store the year
component of a date.
Of course, data types, by themselves are only one piece of the puzzle; in
order to do something with them, you need functions. And MySQL scores high
points there as well, providing over 40 built-in functions to process and
manipulate date and time values. The MySQL date and time API includes functions
to extract different components of a timestamp, to format a timestamp in a
variety of different ways, to obtain the current date and time, to convert
between different date and time formats, and much, much more.
Sadly, this article isn't going to examine the complete date and time API in
MySQL; instead, it's going to focus on a very small subset of this API, the
functions related to performing date and time arithmetic. Flip the page, and
let's get started.