5.5.1 Problem
You want to obtain just a part of a date or a time.
5.5.2 Solution
Use a formatting function such as DATE_FORMAT( ) or TIME_FORMAT( ) with a format string that includes a specifier for the part of the value you want to obtain.
5.5.3 Discussion
MySQL provides several options for decomposing dates or times to obtain their component values. The DATE_FORMAT( ) and TIME_FORMAT( ) functions provide one way to extract individual parts of temporal values:
mysql> SELECT dt, -> DATE_FORMAT(dt,'%Y') AS year, -> DATE_FORMAT(dt,'%d') AS day, -> TIME_FORMAT(dt,'%H') AS hour, -> TIME_FORMAT(dt,'%s') AS second -> FROM datetime_val; +---------------------+------+------+------+--------+ | dt | year | day | hour | second | +---------------------+------+------+------+--------+ | 1970-01-01 00:00:00 | 1970 | 01 | 00 | 00 | | 1987-03-05 12:30:15 | 1987 | 05 | 12 | 15 | | 1999-12-31 09:00:00 | 1999 | 31 | 09 | 00 | | 2000-06-04 15:45:30 | 2000 | 04 | 15 | 30 | +---------------------+------+------+------+--------+
Formatting functions allow you to extract more than one part of a value. For example, to extract the entire date or time from DATETIME values, do this:
mysql> SELECT dt, -> DATE_FORMAT(dt,'%Y-%m-%d') AS 'date part', -> TIME_FORMAT(dt,'%T') AS 'time part' -> FROM datetime_val; +---------------------+------------+-----------+ | dt | date part | time part | +---------------------+------------+-----------+ | 1970-01-01 00:00:00 | 1970-01-01 | 00:00:00 | | 1987-03-05 12:30:15 | 1987-03-05 | 12:30:15 | | 1999-12-31 09:00:00 | 1999-12-31 | 09:00:00 | | 2000-06-04 15:45:30 | 2000-06-04 | 15:45:30 | +---------------------+------------+-----------+
One advantage of using formatting functions is that you can display the extracted values in a different form than that in which they're present in the original values. If you want to present a date differently than in CCYY-MM-DD format or present a time without the seconds part, that's easy to do:
mysql> SELECT ts, -> DATE_FORMAT(ts,'%M %e, %Y') AS 'descriptive date', -> TIME_FORMAT(ts,'%H:%i') AS 'hours/minutes' -> FROM timestamp_val; +----------------+-------------------+---------------+ | ts | descriptive date | hours/minutes | +----------------+-------------------+---------------+ | 19700101000000 | January 1, 1970 | 00:00 | | 19870305123015 | March 5, 1987 | 12:30 | | 19991231090000 | December 31, 1999 | 09:00 | | 20000604154530 | June 4, 2000 | 15:45 | +----------------+-------------------+---------------+
5.5.4 See Also
Recipe 5.6 discusses other functions that may be used to extract single components from dates or times. Recipe 5.7 shows how to use substring functions for component extraction.
Using the mysql Client Program
Writing MySQL-Based Programs
Record Selection Techniques
Working with Strings
Working with Dates and Times
Sorting Query Results
Generating Summaries
Modifying Tables with ALTER TABLE
Obtaining and Using Metadata
Importing and Exporting Data
Generating and Using Sequences
Using Multiple Tables
Statistical Techniques
Handling Duplicates
Performing Transactions
Introduction to MySQL on the Web
Incorporating Query Resultsinto Web Pages
Processing Web Input with MySQL
Using MySQL-Based Web Session Management
Appendix A. Obtaining MySQL Software
Appendix B. JSP and Tomcat Primer
Appendix C. References