Date time functions commonly used in MySQL

Catalog

1. date (date) function

2. Time (time) function

3. Date and time function

4. Date and time comparison

5. Date and time calculation

6. Formatting of date and time

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1. date (date) function

** Return current date ：**CURDATE(), CURRENT_DATE(), CURRENT_DATE

2. Time (time) function

** Return current time ：**CURTIME(), CURRENT_TIME(), CURRENT_TIME

3. Date and time functions

** Returns the current date and time ：**CURRENT_TIMESTAMP(), CURRENT_TIMESTAMP, LOCALTIME(), LOCALTIME, LOCALTIMESTAMP(), LOCALTIMESTAMP, NOW(), SYSDATE()

NOW(), SYSDATE() The difference between ：

NOW() Return to execute the current SQL The time of the statement ：

SYSDATE() Returns the time when the current function is executed ：

SYSDATE() You can pass in a parameter :fsp Indicates whether decimal second precision is included （0~6 position ）

4. Date and time comparison

The output of the above three statements is the same .

Mysql You can directly compare the time size with the string in , As long as your date format is legal .

5. Date and time calculation

**DATE_ADD() function ：** Date and time increase and decrease

Function INTERVAL A positive value after the parameter indicates that the date time increases , A negative value indicates that the date time decreases

**DATEDIFF() function ：** Calculate the difference between two dates

**TIMEDIFF() function ：** Calculate two time differences

6. Formatting of date and time

DATE_FORMAT(date,format) function ：

Commonly used ：DATE_FORMAT(SYSDATE(),‘%Y-%m-%d %H:%i:%s’)

%p：PM or AM;

%r：HH:mm:ss PM Form time ;

%W： Zhou , Zhou Ming , Such as Tuesday;

%w： Zhou ,0-6,0 It's Sunday ;

%j： The number of days in the year in which the current date is located ,3 position （001-366）.

DATE_FORMAT(date,format) and STR_TO_DATE(str,format) function ：

DATE_FORMAT(date,format)： In the database date The data is formatted as String type

STR_TO_DATE(str,format)： Converts the string in the specified time format into DATETIME Type value .str To work with format Keep the format consistent , Otherwise, an error will be reported .

The first return value is String type , The second return value is datetime type .

**YEAR() function ：** Take the year of the date and time