Oracle 5.0, Справочное руководство

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Date and Time Functions
933
Mode First day of week Range Week 1 is the first week …
2 Sunday 1-53 with a Sunday in this year
3 Monday 1-53 with more than 3 days this year
4 Sunday 0-53 with more than 3 days this year
5 Monday 0-53 with a Monday in this year
6 Sunday 1-53 with more than 3 days this year
7 Monday 1-53 with a Monday in this year
mysql> SELECT WEEK('2008-02-20');
-> 7
mysql> SELECT WEEK('2008-02-20',0);
-> 7
mysql> SELECT WEEK('2008-02-20',1);
-> 8
mysql> SELECT WEEK('2008-12-31',1);
-> 53
Note that if a date falls in the last week of the previous year, MySQL returns
0
if you do not use
2
,
3
,
6
, or
7
as the optional
mode
argument:
mysql> SELECT YEAR('2000-01-01'), WEEK('2000-01-01',0);
-> 2000, 0
One might argue that MySQL should return
52
for the
WEEK()
[932] function, because the given
date actually occurs in the 52nd week of 1999. We decided to return
0
instead because we want
the function to return “the week number in the given year.” This makes use of the
WEEK()
[932]
function reliable when combined with other functions that extract a date part from a date.
If you would prefer the result to be evaluated with respect to the year that contains the first day of the
week for the given date, use
0
,
2
,
5
, or
7
as the optional
mode
argument.
mysql> SELECT WEEK('2000-01-01',2);
-> 52
Alternatively, use the
YEARWEEK()
[934] function:
mysql> SELECT YEARWEEK('2000-01-01');
-> 199952
mysql> SELECT MID(YEARWEEK('2000-01-01'),5,2);
-> '52'
•
WEEKDAY(date)
[933]
Returns the weekday index for
date
(
0
= Monday,
1
= Tuesday, …
6
= Sunday).
mysql> SELECT WEEKDAY('2008-02-03 22:23:00');
-> 6
mysql> SELECT WEEKDAY('2007-11-06');
-> 1
•
WEEKOFYEAR(date)
[933]
Returns the calendar week of the date as a number in the range from
1
to
53
.
WEEKOFYEAR()
[933] is a compatibility function that is equivalent to
WEEK(date,3)
[932] .
mysql> SELECT WEEKOFYEAR('2008-02-20');
-> 8
•
YEAR(date)
[933]
Returns the year for
date
, in the range
1000
to
9999
, or
0
for the “zero” date.
mysql> SELECT YEAR('1987-01-01');