MySQL TO_DAYS() Function

  1. Overview
  2. MYSQL
  3. Date Functions
  4. MySQL TO_DAYS() Function

The TO_DAYS() function in MySQL is used to return the number of days between a given date and the "zero" date, which is defined as the start of the Gregorian calendar, i.e., 0000-00-00.

Definition and Usage

  • Purpose: This function calculates and returns the total number of days between the given date and the year 0 (start of the Gregorian calendar).
  • Note: It only works with dates within the Gregorian calendar.

Syntax

TO_DAYS(date)
  • date: The date for which the number of days is calculated. This can be a DATE, DATETIME, or TIMESTAMP value.

Technical Details

  • Works in: From MySQL 4.0 onwards.
  • Return Type: Returns an integer value representing the number of days.
  • Important: The function can only be used with valid dates and will not work with NULL or invalid date formats.

Examples

Example 1: Return the number of days between a given date and year 0

SELECT TO_DAYS("2017-06-20");

Result:

737494

Explanation: The function calculates the total number of days from the year 0 to June 20, 2017, which is 737494 days.

Example 2: Return the number of days for a date-time value

SELECT TO_DAYS("2017-06-20 09:34:00");

Result:

737494

Explanation: The time component (09:34:00) is ignored, and the function still calculates the number of days from the year 0 to June 20, 2017.

Use Cases

  • Date Difference Calculations: When you need to calculate how many days have passed since a certain date.
  • Chronological Data Management: Useful for converting dates into day counts for chronological ordering or comparisons.
  • Event Scheduling: Can be helpful for determining the difference in days between historical or future events.

Related Functions

  • FROM_DAYS(): The opposite of TO_DAYS(). It converts a number of days back into a date.
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