Изучаем mysql: работа с датами и временем

Содержание:

SQL Учебник
Oracle
- What’s the Difference Between SYSDATE and CURRENT_DATE in Oracle?
SQL Справочник
SQL Справочник
CONVERT_TZ(dt,from_tz,to_tz)
UPDATE таблица
- Пример
SQL Учебник
CURTIME()
UNIX_TIMESTAMP(), UNIX_TIMESTAMP(date)
SQL Справочник
Параметр значений
Convert SQL DATE Format Example
- Convert SQL DATE Format Example 2
SQL Справочник
SQL References
WEEK(date[,mode])

SQL Учебник

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Oracle

Sql server order by

There are a few ways to get the current date in Oracle SQL.

Function	Data Type	Returns
SYSDATE	date	Current date and time of the server
CURRENT_DATE	date	Current date and time in the session time zone
CURRENT_TIMESTAMP	timestamp with time zone	Current date and time with time zone in the session time zone
LOCALTIMESTAMP	timestamp	Current date and time in the session time zone
SYSTIMESTAMP	timestamp with time zone	Current date and time of the server

The method you use depends on which data type you want and whether you want the server or session time zone.

Let’s see some examples of these functions.

The results are below (translated to rows to make it easier to compare):

Function	Result
SYSDATE	15-JUL-20
CURRENT_DATE	15-JUL-20
CURRENT_TIMESTAMP	15-JUL-20 12.08.25.095819 AM US/PACIFIC
LOCALTIMESTAMP	15-JUL-20 12.08.25.095819 AM
SYSTIMESTAMP	15-JUL-20 07.08.25.095818 AM +00:00

We can see a few things here:

SYSDATE and CURRENT_DATE show a similar output.
CURRENT_TIMESTAMP and LOCALTIMESTAMP show the same value but one is with the timezone and one is without.

One thing to be aware of is that even though SYSDATE and CURRENT_DATE display the date here, they actually include the time.

To see the time component, we can use TO_CHAR, which shows the difference between the two functions:

Operation	Result
SYSDATE	15-JUL-20
SYSDATE_FULL	2020-07-15 06:51:58
CURRENT_DATE	15-JUL-20
CURRENT_DATE_FULL	2020-07-15 11:51:58

We can see that both dates are the same, but the times are different.

What’s the Difference Between SYSDATE and CURRENT_DATE in Oracle?

These two functions look like they show the same thing. So how are they different?

SYSDATE is based on the server, and CURRENT_DATE is based on the user’s session.

This means if the user is based in New York and the database server is in London, the SYSDATE function will return the London date and time, and the CURRENT_DATE function will return the New York date and time.

SQL Справочник

Примеры использования инструкции select (transact-sql)

SQL Ключевые слова
ADD
ADD CONSTRAINT
ALTER
ALTER COLUMN
ALTER TABLE
ALL
AND
ANY
AS
ASC
BACKUP DATABASE
BETWEEN
CASE
CHECK
COLUMN
CONSTRAINT
CREATE
CREATE DATABASE
CREATE INDEX
CREATE OR REPLACE VIEW
CREATE TABLE
CREATE PROCEDURE
CREATE UNIQUE INDEX
CREATE VIEW
DATABASE
DEFAULT
DELETE
DESC
DISTINCT
DROP
DROP COLUMN
DROP CONSTRAINT
DROP DATABASE
DROP DEFAULT
DROP INDEX
DROP TABLE
DROP VIEW
EXEC
EXISTS
FOREIGN KEY
FROM
FULL OUTER JOIN
GROUP BY
HAVING
IN
INDEX
INNER JOIN
INSERT INTO
INSERT INTO SELECT
IS NULL
IS NOT NULL
JOIN
LEFT JOIN
LIKE
LIMIT
NOT
NOT NULL
OR
ORDER BY
OUTER JOIN
PRIMARY KEY
PROCEDURE
RIGHT JOIN
ROWNUM
SELECT
SELECT DISTINCT
SELECT INTO
SELECT TOP
SET
TABLE
TOP
TRUNCATE TABLE
UNION
UNION ALL
UNIQUE
UPDATE
VALUES
VIEW
WHERE

MySQL Функции
Функции строк
ASCII
CHAR_LENGTH
CHARACTER_LENGTH
CONCAT
CONCAT_WS
FIELD
FIND_IN_SET
FORMAT
INSERT
INSTR
LCASE
LEFT
LENGTH
LOCATE
LOWER
LPAD
LTRIM
MID
POSITION
REPEAT
REPLACE
REVERSE
RIGHT
RPAD
RTRIM
SPACE
STRCMP
SUBSTR
SUBSTRING
SUBSTRING_INDEX
TRIM
UCASE
UPPER
Функции чисел
ABS
ACOS
ASIN
ATAN
ATAN2
AVG
CEIL
CEILING
COS
COT
COUNT
DEGREES
DIV
EXP
FLOOR
GREATEST
LEAST
LN
LOG
LOG10
LOG2
MAX
MIN
MOD
PI
POW
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SUM
TAN
TRUNCATE
Функции дат
ADDDATE
ADDTIME
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
MAKETIME
MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
PERIOD_DIFF
QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
SYSDATE
TIME
TIME_FORMAT
TIME_TO_SEC
TIMEDIFF
TIMESTAMP
TO_DAYS
WEEK
WEEKDAY
WEEKOFYEAR
YEAR
YEARWEEK
Функции расширений
BIN
BINARY
CASE
CAST
COALESCE
CONNECTION_ID
CONV
CONVERT
CURRENT_USER
DATABASE
IF
IFNULL
ISNULL
LAST_INSERT_ID
NULLIF
SESSION_USER
SYSTEM_USER
USER
VERSION

SQL Server функции
Функции строк
ASCII
CHAR
CHARINDEX
CONCAT
Concat with +
CONCAT_WS
DATALENGTH
DIFFERENCE
FORMAT
LEFT
LEN
LOWER
LTRIM
NCHAR
PATINDEX
QUOTENAME
REPLACE
REPLICATE
REVERSE
RIGHT
RTRIM
SOUNDEX
SPACE
STR
STUFF
SUBSTRING
TRANSLATE
TRIM
UNICODE
UPPER
Функции чисел
ABS
ACOS
ASIN
ATAN
ATN2
AVG
CEILING
COUNT
COS
COT
DEGREES
EXP
FLOOR
LOG
LOG10
MAX
MIN
PI
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SQUARE
SUM
TAN
Функции дат
CURRENT_TIMESTAMP
DATEADD
DATEDIFF
DATEFROMPARTS
DATENAME
DATEPART
DAY
GETDATE
GETUTCDATE
ISDATE
MONTH
SYSDATETIME
YEAR
Функции расширений
CAST
COALESCE
CONVERT
CURRENT_USER
IIF
ISNULL
ISNUMERIC
NULLIF
SESSION_USER
SESSIONPROPERTY
SYSTEM_USER
USER_NAME

MS Access функции
Функции строк
Asc
Chr
Concat with &
CurDir
Format
InStr
InstrRev
LCase
Left
Len
LTrim
Mid
Replace
Right
RTrim
Space
Split
Str
StrComp
StrConv
StrReverse
Trim
UCase
Функции чисел
Abs
Atn
Avg
Cos
Count
Exp
Fix
Format
Int
Max
Min
Randomize
Rnd
Round
Sgn
Sqr
Sum
Val
Функции дат
Date
DateAdd
DateDiff
DatePart
DateSerial
DateValue
Day
Format
Hour
Minute
Month
MonthName
Now
Second
Time
TimeSerial
TimeValue
Weekday
WeekdayName
Year
Другие функции
CurrentUser
Environ
IsDate
IsNull
IsNumeric

SQL ОператорыSQL Типы данныхSQL Краткий справочник

SQL Справочник

Sql join в примерах с описанием

SQL ОператорыSQL Типы данныхSQL Краткий справочник

CONVERT_TZ(dt,from_tz,to_tz)

This converts a datetime value dt from the time zone given by from_tz to the time zone given by to_tz and returns the resulting value. This function returns NULL if the arguments are invalid.

mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','GMT','MET');
+---------------------------------------------------------+
| CONVERT_TZ('2004-01-01 12:00:00','GMT','MET')           |
+---------------------------------------------------------+
| 2004-01-01 13:00:00                                     |
+---------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','+00:00','+10:00');
+---------------------------------------------------------+
| CONVERT_TZ('2004-01-01 12:00:00','+00:00','+10:00')     |
+---------------------------------------------------------+
| 2004-01-01 22:00:00                                     |
+---------------------------------------------------------+
1 row in set (0.00 sec)

UPDATE таблица

Следующая инструкция SQL обновляет первого клиента (CustomerID = 1) с новым контактным лицом и новым городом.

Пример

UPDATE Customers
SET ContactName = ‘Alfred Schmidt’, City= ‘Frankfurt’
WHERE CustomerID = 1;

Выбор из таблицы «Customers» теперь будет выглядеть следующим образом:

CustomerID	CustomerName	ContactName	Address	City	PostalCode	Country
1	Alfreds Futterkiste	Alfred Schmidt	Obere Str. 57	Frankfurt	12209	Germany
2	Ana Trujillo Emparedados y helados	Ana Trujillo	Avda. de la Constitución 2222	México D.F.	05021	Mexico
3	Antonio Moreno Taquería	Antonio Moreno	Mataderos 2312	México D.F.	05023	Mexico
4	Around the Horn	Thomas Hardy	120 Hanover Sq.	London	WA1 1DP	UK
5	Berglunds snabbköp	Christina Berglund	Berguvsvägen 8	Luleå	S-958 22	Sweden

SQL Учебник

CURTIME()

Returns the current time as a value in ‘HH:MM:SS’ or HHMMSS format, depending on whether the function is used in a string or in a numeric context. The value is expressed in the current time zone.

mysql> SELECT CURTIME();
+---------------------------------------------------------+
| CURTIME()                                               |
+---------------------------------------------------------+
| 23:50:26                                                |
+---------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT CURTIME() + 0;
+---------------------------------------------------------+
| CURTIME() + 0                                           |
+---------------------------------------------------------+
| 235026                                                  |
+---------------------------------------------------------+
1 row in set (0.00 sec)

UNIX_TIMESTAMP(), UNIX_TIMESTAMP(date)

If called with no argument, this function returns a Unix timestamp (seconds since ‘1970-01-01 00:00:00’ UTC) as an unsigned integer. If UNIX_TIMESTAMP() is called with a date argument, it returns the value of the argument as seconds since ‘1970-01-01 00:00:00’ UTC. date may be a DATE string, a DATETIME string, a TIMESTAMP, or a number in the format YYMMDD or YYYYMMDD.

mysql> SELECT UNIX_TIMESTAMP();
+---------------------------------------------------------+
| UNIX_TIMESTAMP()                                        |
+---------------------------------------------------------+
| 882226357                                               |
+---------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT UNIX_TIMESTAMP('1997-10-04 22:23:00');
+---------------------------------------------------------+
| UNIX_TIMESTAMP('1997-10-04 22:23:00')                   |
+---------------------------------------------------------+
| 875996580                                               |
+---------------------------------------------------------+
1 row in set (0.00 sec)

SQL Справочник

SQL ОператорыSQL Типы данныхSQL Краткий справочник

Параметр значений

Параметр

Описание

date

Требуемый. Дата будет отформатирована

format

Требуемый. Формат для использования. Может быть одно или комбинация следующих значений:

Формат	Описание
%a	Сокращенное название дня недели (от ВС до СБ)
%b	Сокращенное название месяца (Янв-Дек)
%c	Числовое название месяца (от 0 до 12)
%D	День месяца как числовое значение, за которым следует суффикс (1-й, 2-й, 3-й, …)
%d	День месяца как числовое значение (от 01 до 31)
%e	День месяца как числовое значение (от 0 до 31)
%f	Микросекунды (от 000000 до 999999)
%H	Час (с 00 до 23)
%h	Час (с 00 до 12)
%I	Час (с 00 до 12)
%i	Минуты (с 00 до 59)
%j	День года (от 001 до 366)
%k	Час (от 0 до 23)
%l	Час (от 1 до 12)
%M	Название месяца полностью (Январь-Декабрь)
%m	Название месяца в виде числового значения (от 00 до 12)
%p	AM или PM
%r	Время в 12-часовом AM или PM формат (hh:mm:ss AM/PM)
%S	Секунды (от 00 до 59)
%s	Секунды (от 00 до 59)
%T	Время в 24-часовом формат (hh:mm:ss)
%U	Неделя, где воскресенье — это первый день недели (с 00 до 53)
%u	Неделя, где понедельник — это первый день недели (с 00 до 53)
%V	Неделя, где воскресенье — это первый день недели (с 01 по 53). Используется с %X
%v	Неделя, где понедельник — это первый день недели (с 01 по 53). Используется с %X
%W	Название дня недели полностью (с воскресенья по субботу)
%w	День недели, где воскресенье=0 и суббота=6
%X	Год для недели, где воскресенье — это первый день недели. Используется с %V
%x	Год для недели, где понедельник — это первый день недели. Используется с %V
%Y	Год как числовое, 4-значное значение
%y	Год как числовое, 2-значное значение

Convert SQL DATE Format Example

Before we go toward the practical example, let me explain to you the available list of Convert date format in Sql Server. For this demonstration, we are going to write different SQL Date format Queries using CONVERT, and FORMAT function. The CONVERT function provides different formatting styles to format date and time.

Without Century (yy)	With Century (yyyy)	Input/Output	Standard
–	0 to 100	mon dd yyyy hh:miAM (or PM)	This is the Default for both datetime, and smalldatetime
1	101	1 = mm/dd/yy101 = mm/dd/yyyy	U.S.
2	102	2 = yy.mm.dd102 = yyyy.mm.dd	ANSI
3	103	3 = dd/mm/yy103 = dd/mm/yyyy	British/French
4	104	4 = dd.mm.yy104 = dd.mm.yyyy	German
5	105	5 = dd-mm-yy105 = dd-mm-yyyy	Italian
6	106	6 = dd mon yy106 = dd mon yyyy	–
7	107	7 = Mon dd, yy107 = Mon dd, yyyy	–
8	108	hh:mi:ss	–
–	9 or 109	mon dd yyyy hh:mi:ss:mmmmAM (or PM)	Default + milliseconds
10	110	10 = mm-dd-yy110 = mm-dd-yyyy	USA
11	111	11 = yy/mm/dd111 = yyyy/mm/dd	JAPAN
12	112	12 = yymmdd112 = yyyymmdd	ISO
–	13 or 113	dd mon yyyy hh:mi:ss:mmm(24h)	Europe Default + millisecond
14	114	hh:mi:ss:mmm(24h)	–
–	20 or 120	yyyy-mm-dd hh:mi:ss(24h)	ODBC canonical
–	21 or 121	yyyy-mm-dd hh:mi:ss.mmm(24h)	ODBC canonical with milliseconds. This is the Default for time, date, datetime2, and datetimeoffset
–	126	yyyy-mm-ddThh:mi:ss.mmm (no Spaces)	ISO8601
–	127	yyyy-mm-ddThh:mi:ss.mmmZ (no Spaces)	ISO8601 with time zone Z
–	130	dd mon yyyy hh:mi:ss:mmmAM	Hijri
–	131	dd/mm/yyyy hh:mi:ss:mmmAM	Hijri

Convert SQL DATE Format Example 2

This example query covers few more date formats in Convert function

In this example query, we are showing few other date formats in Convert function are

Some other convert date format

The following are the list of remaining formatting options available in convert function for date format.

SQL Справочник

SQL ОператорыSQL Типы данныхSQL Краткий справочник

SQL References

SQL Keywords
ADD
ADD CONSTRAINT
ALTER
ALTER COLUMN
ALTER TABLE
ALL
AND
ANY
AS
ASC
BACKUP DATABASE
BETWEEN
CASE
CHECK
COLUMN
CONSTRAINT
CREATE
CREATE DATABASE
CREATE INDEX
CREATE OR REPLACE VIEW
CREATE TABLE
CREATE PROCEDURE
CREATE UNIQUE INDEX
CREATE VIEW
DATABASE
DEFAULT
DELETE
DESC
DISTINCT
DROP
DROP COLUMN
DROP CONSTRAINT
DROP DATABASE
DROP DEFAULT
DROP INDEX
DROP TABLE
DROP VIEW
EXEC
EXISTS
FOREIGN KEY
FROM
FULL OUTER JOIN
GROUP BY
HAVING
IN
INDEX
INNER JOIN
INSERT INTO
INSERT INTO SELECT
IS NULL
IS NOT NULL
JOIN
LEFT JOIN
LIKE
LIMIT
NOT
NOT NULL
OR
ORDER BY
OUTER JOIN
PRIMARY KEY
PROCEDURE
RIGHT JOIN
ROWNUM
SELECT
SELECT DISTINCT
SELECT INTO
SELECT TOP
SET
TABLE
TOP
TRUNCATE TABLE
UNION
UNION ALL
UNIQUE
UPDATE
VALUES
VIEW
WHERE

MySQL Functions
String Functions
ASCII
CHAR_LENGTH
CHARACTER_LENGTH
CONCAT
CONCAT_WS
FIELD
FIND_IN_SET
FORMAT
INSERT
INSTR
LCASE
LEFT
LENGTH
LOCATE
LOWER
LPAD
LTRIM
MID
POSITION
REPEAT
REPLACE
REVERSE
RIGHT
RPAD
RTRIM
SPACE
STRCMP
SUBSTR
SUBSTRING
SUBSTRING_INDEX
TRIM
UCASE
UPPER

Numeric Functions
ABS
ACOS
ASIN
ATAN
ATAN2
AVG
CEIL
CEILING
COS
COT
COUNT
DEGREES
DIV
EXP
FLOOR
GREATEST
LEAST
LN
LOG
LOG10
LOG2
MAX
MIN
MOD
PI
POW
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SUM
TAN
TRUNCATE

Date Functions
ADDDATE
ADDTIME
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
MAKETIME
MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
PERIOD_DIFF
QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
SYSDATE
TIME
TIME_FORMAT
TIME_TO_SEC
TIMEDIFF
TIMESTAMP
TO_DAYS
WEEK
WEEKDAY
WEEKOFYEAR
YEAR
YEARWEEK

Advanced Functions
BIN
BINARY
CASE
CAST
COALESCE
CONNECTION_ID
CONV
CONVERT
CURRENT_USER
DATABASE
IF
IFNULL
ISNULL
LAST_INSERT_ID
NULLIF
SESSION_USER
SYSTEM_USER
USER
VERSION

SQL Server Functions
String Functions
ASCII
CHAR
CHARINDEX
CONCAT
Concat with +
CONCAT_WS
DATALENGTH
DIFFERENCE
FORMAT
LEFT
LEN
LOWER
LTRIM
NCHAR
PATINDEX
QUOTENAME
REPLACE
REPLICATE
REVERSE
RIGHT
RTRIM
SOUNDEX
SPACE
STR
STUFF
SUBSTRING
TRANSLATE
TRIM
UNICODE
UPPER

Numeric Functions
ABS
ACOS
ASIN
ATAN
ATN2
AVG
CEILING
COUNT
COS
COT
DEGREES
EXP
FLOOR
LOG
LOG10
MAX
MIN
PI
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SQUARE
SUM
TAN

Date Functions
CURRENT_TIMESTAMP
DATEADD
DATEDIFF
DATEFROMPARTS
DATENAME
DATEPART
DAY
GETDATE
GETUTCDATE
ISDATE
MONTH
SYSDATETIME
YEAR

Advanced Functions
CAST
COALESCE
CONVERT
CURRENT_USER
IIF
ISNULL
ISNUMERIC
NULLIF
SESSION_USER
SESSIONPROPERTY
SYSTEM_USER
USER_NAME

MS Access Functions
String Functions
Asc
Chr
Concat with &
CurDir
Format
InStr
InstrRev
LCase
Left
Len
LTrim
Mid
Replace
Right
RTrim
Space
Split
Str
StrComp
StrConv
StrReverse
Trim
UCase

Numeric Functions
Abs
Atn
Avg
Cos
Count
Exp
Fix
Format
Int
Max
Min
Randomize
Rnd
Round
Sgn
Sqr
Sum
Val

Date Functions
Date
DateAdd
DateDiff
DatePart
DateSerial
DateValue
Day
Format
Hour
Minute
Month
MonthName
Now
Second
Time
TimeSerial
TimeValue
Weekday
WeekdayName
Year

Other Functions
CurrentUser
Environ
IsDate
IsNull
IsNumeric

SQL Quick Ref

WEEK(date[,mode])

This function returns the week number for date. The two-argument form of WEEK() allows you to specify whether the week starts on a Sunday or a Monday and whether the return value should be in the range from 0 to 53 or from 1 to 53. If the mode argument is omitted, the value of the default_week_format system variable is used

Mode	First Day of week	Range	Week 1 is the first week.
Sunday	0-53	with a Sunday in this year
1	Monday	0-53	with more than 3 days this year
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('1998-02-20');
+---------------------------------------------------------+
| WEEK('1998-02-20')                                      |
+---------------------------------------------------------+
| 7                                                       |
+---------------------------------------------------------+
1 row in set (0.00 sec)