SQL Server/T-SQL Tutorial/Date Functions/DATEADD — различия между версиями

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Текущая версия на 10:23, 26 мая 2010

Calculating the First Day of the Month

37>
38> CREATE TABLE employee(
39>    id          INTEGER NOT NULL PRIMARY KEY,
40>    first_name  VARCHAR(10),
41>    last_name   VARCHAR(10),
42>    salary      DECIMAL(10,2),
43>    start_Date  DATETIME,
44>    region      VARCHAR(10),
45>    city        VARCHAR(20),
46>    managerid   INTEGER
47> );
48> GO
1> INSERT INTO employee VALUES (1, "Jason" ,  "Martin", 5890,"2005-03-22","North","Vancouver",3);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (2, "Alison",  "Mathews",4789,"2003-07-21","South","Utown",4);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (3, "James" ,  "Smith",  6678,"2001-12-01","North","Paris",5);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (4, "Celia" ,  "Rice",   5567,"2006-03-03","South","London",6);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (5, "Robert",  "Black",  4467,"2004-07-02","East","Newton",7);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (6, "Linda" ,  "Green" , 6456,"2002-05-19","East","Calgary",8);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (7, "David" ,  "Larry",  5345,"2008-03-18","West","New York",9);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (8, "James" ,  "Cat",    4234,"2007-07-17","West","Regina",9);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (9, "Joan"  ,  "Act",    6123,"2001-04-16","North","Toronto",10);
2> GO
(1 rows affected)
1>
2> select * from employee;
3> GO
id          first_name last_name  salary       start_Date              region     city                 managerid
----------- ---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
          1 Jason      Martin          5890.00 2005-03-22 00:00:00.000 North      Vancouver                      3
          2 Alison     Mathews         4789.00 2003-07-21 00:00:00.000 South      Utown                          4
          3 James      Smith           6678.00 2001-12-01 00:00:00.000 North      Paris                          5
          4 Celia      Rice            5567.00 2006-03-03 00:00:00.000 South      London                         6
          5 Robert     Black           4467.00 2004-07-02 00:00:00.000 East       Newton                         7
          6 Linda      Green           6456.00 2002-05-19 00:00:00.000 East       Calgary                        8
          7 David      Larry           5345.00 2008-03-18 00:00:00.000 West       New York                       9
          8 James      Cat             4234.00 2007-07-17 00:00:00.000 West       Regina                         9
          9 Joan       Act             6123.00 2001-04-16 00:00:00.000 North      Toronto                       10
(9 rows affected)
1>
2>
3>
4> SELECT
5>   CONVERT (char (6), Start_Date, 112) + "01"
6> FROM
7>     Employee
8>
9> GO
--------
20050301
20030701
20011201
20060301
20040701
20020501
20080301
20070701
20010401
(9 rows affected)
1>
2>
3> drop table employee;
4> GO


DATEADD adds a time interval to a date in order to arrive at the new date: DATEADD(datepart,number,date)

Parts of the date.
Date Part        Description         Value Range
YY               Year                1753 to 9999
QQ               Quarter             1 to 4
MM               Month               1 to 12
DY               Day of year         1 to 366
DD               Day of month        1 to 31
WK               Week of year        1 to 53
DW               Weekday             1 to 7 or Sun. to Sat.
HH               Hour                0 to 23 (military time)
MI               Minute              0 to 59
SS               Second              0 to 59
MS               Millisecond         0 to 999

34> SELECT DATEADD(DY,30,"10/01/97")
35> GO
-----------------------
1997-10-31 00:00:00.000
(1 rows affected)
1>


DATEADD adds or subtract a number of days, months, or years from a specific date.

To subtract days, use a negative number in the second parameter
9> SELECT DATEADD(dd,12,"24 March 1964")
10> GO
-----------------------
1964-04-05 00:00:00.000
(1 rows affected)
The syntax for DATEADD requires 3 parameters.
DATEADD(what_to_add,number_to_add,date_to_add_it_to)
The first parameter can define what you are wishing to add to the date.


Determine the date 90 days after April

6>
7> SELECT DATEADD(Day, 90, "4-29-1988")
8> GO
-----------------------
1988-07-28 00:00:00.000
(1 rows affected)
1>


Finding the Last Day of the Month

3>
4> CREATE TABLE employee(
5>    id          INTEGER NOT NULL PRIMARY KEY,
6>    first_name  VARCHAR(10),
7>    last_name   VARCHAR(10),
8>    salary      DECIMAL(10,2),
9>    start_Date  DATETIME,
10>    region      VARCHAR(10),
11>    city        VARCHAR(20),
12>    managerid   INTEGER
13> );
14> GO
1> INSERT INTO employee VALUES (1, "Jason" ,  "Martin", 5890,"2005-03-22","North","Vancouver",3);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (2, "Alison",  "Mathews",4789,"2003-07-21","South","Utown",4);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (3, "James" ,  "Smith",  6678,"2001-12-01","North","Paris",5);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (4, "Celia" ,  "Rice",   5567,"2006-03-03","South","London",6);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (5, "Robert",  "Black",  4467,"2004-07-02","East","Newton",7);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (6, "Linda" ,  "Green" , 6456,"2002-05-19","East","Calgary",8);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (7, "David" ,  "Larry",  5345,"2008-03-18","West","New York",9);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (8, "James" ,  "Cat",    4234,"2007-07-17","West","Regina",9);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (9, "Joan"  ,  "Act",    6123,"2001-04-16","North","Toronto",10);
2> GO
(1 rows affected)
1>
2> select * from employee;
3> GO
id          first_name last_name  salary       start_Date              region     city                 managerid
----------- ---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
          1 Jason      Martin          5890.00 2005-03-22 00:00:00.000 North      Vancouver                      3
          2 Alison     Mathews         4789.00 2003-07-21 00:00:00.000 South      Utown                          4
          3 James      Smith           6678.00 2001-12-01 00:00:00.000 North      Paris                          5
          4 Celia      Rice            5567.00 2006-03-03 00:00:00.000 South      London                         6
          5 Robert     Black           4467.00 2004-07-02 00:00:00.000 East       Newton                         7
          6 Linda      Green           6456.00 2002-05-19 00:00:00.000 East       Calgary                        8
          7 David      Larry           5345.00 2008-03-18 00:00:00.000 West       New York                       9
          8 James      Cat             4234.00 2007-07-17 00:00:00.000 West       Regina                         9
          9 Joan       Act             6123.00 2001-04-16 00:00:00.000 North      Toronto                       10
(9 rows affected)
1>
2>
3>
4>
5> SELECT
6>   DATEADD (dd, -1,
7>     DATEADD (mm, 1,
8>       CONVERT (char (6), Start_Date, 112) + "01"))
9> FROM
10>     Employee
11> GO
-----------------------
2005-03-31 00:00:00.000
2003-07-31 00:00:00.000
2001-12-31 00:00:00.000
2006-03-31 00:00:00.000
2004-07-31 00:00:00.000
2002-05-31 00:00:00.000
2008-03-31 00:00:00.000
2007-07-31 00:00:00.000
2001-04-30 00:00:00.000
(9 rows affected)
1>
2>
3> drop table employee;
4> GO


select DATEADD(day, 1, "2002-35:00")

3> select DATEADD(day, 1, "2002-09-30 11:35:00")
4> GO
-----------------------
2002-10-01 11:35:00.000
(1 rows affected)


SELECT DATEADD(day, 14, GETDATE())

3> SELECT DATEADD(day, 14, GETDATE())
4> GO
-----------------------
2008-08-31 13:20:40.540
(1 rows affected)
1>


select DATEADD(hour, 1, "2002-35:00")

2>
3> select DATEADD(hour, 1, "2002-09-30 11:35:00")
4> GO
-----------------------
2002-09-30 12:35:00.000
(1 rows affected)


select DATEADD(minute, 1, "2002-35:00")

2>
3>
4> select DATEADD(minute, 1, "2002-09-30 11:35:00")
5> GO
-----------------------
2002-09-30 11:36:00.000
(1 rows affected)


select DATEADD(month, 1, "2002-35:00")

2>
3>
4> select DATEADD(month, 1, "2002-09-30 11:35:00")
5> GO
-----------------------
2002-10-30 11:35:00.000
(1 rows affected)


select DATEADD(month, -1, "2002-35:00") (Minus)

2>
3> select DATEADD(month, -1, "2002-09-30 11:35:00")
4> GO
-----------------------
2002-08-30 11:35:00.000
(1 rows affected)


select DATEADD(quarter, 1, "2002-35:00")

2>
3> select DATEADD(quarter, 1, "2002-09-30 11:35:00")
4> GO
-----------------------
2002-12-30 11:35:00.000
(1 rows affected)


select DATEADD(second, 1, "2002-35:00")

2>
3> select DATEADD(second, 1, "2002-09-30 11:35:00")
4> GO
-----------------------
2002-09-30 11:35:01.000
(1 rows affected)


select DATEADD(week, 1, "2002-35:00")

2>
3> select DATEADD(week, 1, "2002-09-30 11:35:00")
4> GO
-----------------------
2002-10-07 11:35:00.000
(1 rows affected)


select DATEADD(year, 1, "2002-35:00")

2>
3> select DATEADD(year, 1, "2002-09-30 11:35:00")
4> GO
-----------------------
2003-09-30 11:35:00.000
(1 rows affected)


select DATEADD(year, 1.5, "2002-35:00")

2>
3> select  DATEADD(year, 1.5, "2002-09-30 11:35:00")
4> GO
-----------------------
2003-09-30 11:35:00.000
(1 rows affected)