MySQL DATE type (from EBEY)

We usually dealing with the data, the date of the general will encounter this point. Date format is the mysql date ().

MySQL DATE data type Description:

1, MySQL DATEis used to manage five times the value of the date data type one. MySQL uses the yyyy-mm-ddformat to store date values. This format is fixed and can not change it .

For example, some people may prefer to use mm-dd-yyyyformat, but unfortunately, can not be used directly. Instead of a way: follow the standard date format and use the DATE_FORMAT function in the desired format to format dates.

2, MySQL using 3bytes to store DATEvalues. DATERange of values is 1000-01-01to 9999-12-31. To store date values beyond this range, it is necessary to use a non-time data type,

Such as integers, for example three, respectively, to store data year, month, and day. Also need to create a storage function to simulate the built-in date functions provided by MySQL, this is not recommended.

3, when the strict mode is disabled, MySQL any invalid date (for example 2015-02-30) converted to zero date value 0000-00-00. (We all know that the year is not 30 February)

First, to get the current date and time, use NOW () function.

SELECT NOW() AS cur_time;

Second, to obtain DATETIME date part of the value, use DATE() the function.

SELECT DATE(NOW()) AS cur_date;

Third, we should get the current system date, you can use CURDATE () function

SELECT CURDATE();

Fourth, to format the date values, may be used DATE_FORMAT function. The following statement uses the date format mode ％m/％d/％Y , the date format is: mm/dd/yyyy :

SELECT DATE_FORMAT(NOW(), '%d/%m/%Y') AS today;

V. To calculate the number of days between two dates values, may be used DATEDIFF functions:

SELECT DATEDIFF('2015-11-04','2014-11-04') days;

Sixth, to add days, weeks, months, years, until a date value, you can use DATE_ADD function:

SELECT 
    '2018-01-01' start,
    DATE_ADD('2018-01-01', INTERVAL 1 DAY) 'one day later',
    DATE_ADD('2018-01-01', INTERVAL 1 WEEK) 'one week later',
    DATE_ADD('2018-01-01', INTERVAL 1 MONTH) 'one month later',
    DATE_ADD('2018-01-01', INTERVAL 1 YEAR) 'one year later';

Seven, can be used DATE_SUB subtracts from the date of the interval values:

SELECT 
    '2018-01-01' start,
    DATE_SUB('2018-01-01', INTERVAL 1 DAY) 'one day before',
    DATE_SUB('2018-01-01', INTERVAL 1 WEEK) 'one week before',
    DATE_SUB('2018-01-01', INTERVAL 1 MONTH) 'one month before',
    DATE_SUB('2018-01-01', INTERVAL 1 YEAR) 'one year before';

Eight, if you want to get a date value date, month, quarter and year, you can use the corresponding functions: DAY, MONTH, QUARTER and YEAR, as follows:

SELECT DAY('2020-01-04') day,
       MONTH('2020-01-04') month,
       QUARTER('2020-01-04') quarter,
       YEAR('2020-01-04') year;

Nine, if you want to get information week. Can WEEK return a few weeks function, WEEKDAYthe function returns the weekday index, WEEKOFYEARthe function returns the Week.

SELECT 
    WEEKDAY('2020-01-04') weekday,
    WEEK('2020-01-04') week,
    WEEKOFYEAR('2020-01-04') weekofyear;

Other relevant information function can check their dates.

MySQL DATE type (from EBEY)

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