The most basic function types in the MySQL database

This article mainly describes the practical application and specific operations of the mathematical and datetime functions in the MySQL database. If you are interested in the actual operations of these two functions, you can browse the following articles and hope they will help you.

Function types in MySQL Databases: Mathematics

ABS (number2) // absolute value

BIN (decimal_number) // convert decimal to binary

CEILING (number2) // rounded up

CONV (number2, from_base, to_base) // hexadecimal conversion

FLOOR (number2) // round down

FORMAT (number, decimal_places) // number of reserved decimal places

HEX (DecimalNumber) // convert to hexadecimal

Note: HEX () can input a string, returns its ASC-11 code, such as HEX ('def ') returns 4142143

You can also input a decimal integer to return its hexadecimal encoding. For example, HEX (25) returns 19.

LEAST (number, number2 [,...]) // calculates the minimum value.

MOD (numerator, denominator) // evaluate the remainder

POWER (number, power) // Exponent

RAND ([seed]) // Random Number

ROUND (number [, decimals]) // rounding, decimals is the number of decimal places]

Note: The return type is not an integer, for example:

(1) The default value is integer.

 
 

  
  
MySQL> select round(1.23);  
  
  
+-------------+ | round(1.23) | +-------------+ | 1 | +-------------+ 1 row in set (0.00 sec) MySQL> select round(1.56);  
  
  
+-------------+ | round(1.56) | +-------------+ | 2 | +-------------+ 1 row in set (0.00 sec)   
 
 

(2) the number of decimal places can be set to return floating point data.

 
 

  
  
MySQL> select round(1.567,2);   
  
  
+----------------+ | round(1.567,2) | +----------------+ | 1.57 | +----------------+ 1 row in set (0.00 sec)   
 
 

SIGN (number2) // return SIGN, positive and negative or 0

SQRT (number2) // Square

Function types in MySQL database: Date and Time

ADDTIME (date2, time_interval) // Add time_interval to date2

CONVERT_TZ (datetime2, fromTZ, toTZ) // convert the time zone

CURRENT_DATE () // current date

CURRENT_TIME () // current time

CURRENT_TIMESTAMP () // current Timestamp

DATE (datetime) // return the DATE part of datetime

DATE_ADD (date2, INTERVAL d_value d_type) // Add a date or time in date2

DATE_FORMAT (datetime, FormatCodes) // display datetime in formatcodes format

DATE_SUB (date2, INTERVAL d_value d_type) // subtract a time from date2

DATEDIFF (date1, date2) // two date differences

DAY (date) // returns the DAY of the date

DAYNAME (date) // english week

DAYOFWEEK (date) // Week (1-7), 1 is Sunday

DAYOFYEAR (date) // The day of the year

EXTRACT (interval_name FROM date) // EXTRACT the specified part of the date FROM date

MAKEDATE (year, day) // specifies the day of the year and year to generate a date string.

MAKETIME (hour, minute, second) // generate a time string

MONTHNAME (date) // name of the English month

NOW () // current time

SEC_TO_TIME (seconds) // converts seconds to time

STR_TO_DATE (string, format) // convert string to time, which is displayed in format

TIMEDIFF (datetime1, datetime2) // two time difference

TIME_TO_SEC (time) // time to seconds]

WEEK (date_time [, start_of_week]) // WEEK

YEAR (datetime) // YEAR

DAYOFMONTH (datetime) // The day of the month

HOUR (datetime) // HOUR

LAST_DAY (date) // the last date of the Month of date

MICROSECOND (datetime) // MICROSECOND

MONTH (datetime) // MONTH

MINUTE (datetime) // MINUTE

Appendix: available types in INTERVAL

DAY, DAY_HOUR, DAY_MINUTE, DAY_SECOND, HOUR, HOUR_MINUTE, HOUR_SECOND, MINUTE, MINUTE_SECOND, MONTH, SECOND, YEAR

The above content is an introduction to the function types in the MySQL database. I hope you will have some gains.