Beginning SQL

Chapter 5
Date Functions
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Sometimes it’s quite useful to be able to extract individual parts of a date, such as day of the month,
month, or year. To do this, SQL provides the DAY(), MONTH(), and YEAR() functions. These are supported
by all of the database systems except Oracle.
These functions perform in the same manner, and the syntax for each is as follows:
DAY(date)
MONTH(date)
YEAR(date)
The following code displays the DateOfBirth of each film club member, as well as the day of the month,
month, and year of their birth:
SELECT DateOfBirth, DAY(DateOfBirth), MONTH(DateOfBirth), YEAR(DateOfBirth)
FROM MemberDetails
ORDER BY YEAR(DateOfBirth);
Executing the preceding statement provides the following results:
DateOfBirth DAY(DateOfBirth) MONTH(DateOfBirth) YEAR(DateOfBirth)
1937-01-20 20 1 1937
1945-06-09 9 6 1945
1952-10-05 5 10 1952
1953-08-25 25 8 1953
1956-08-07 7 8 1956
1956-10-21 21 10 1956
1967-10-05 5 10 1967
1974-05-27 27 5 1974
1977-01-09 9 1 1977
1992-07-17 17 7 1992
1994-05-28 28 5 1994
1997-05-28 28 5 1997
Notice the use of a date function in the ORDER BY clause, which allows you to order the results (by year
in this case). The first row of the results is empty because the DateOfBirth column in one of the rows
contains a NULL value.
Most database systems contain a large number of date- and time-related functions, so it’s worth checking
the database help files or product documentation to see what particular functions your system has.