time (Transact-SQL)

مقالة
08/28/2013

Defines a time of a day. The time is without time zone awareness and is based on a 24-hour clock.

time Description

Syntax

time [ (fractional second precision) ]

Usage

DECLARE @MyTime time(7)

CREATE TABLE Table1 ( Column1 time(7) )

fractional seconds precision

Specifies the number of digits for the fractional part of the seconds.

This can be an integer from 0 to 7.

The default fractional precision is 7 (100ns).

Default string literal format

(used for down-level client)

hh:mm:ss[.nnnnnnn]

For more information, see the "Backward Compatibility for Down-level Clients" section that follows..

Range

00:00:00.0000000 through 23:59:59.9999999

Element ranges

hh is two digits, ranging from 0 to 23, that represent the hour.

mm is two digits, ranging from 0 to 59, that represent the minute.

ss is two digits, ranging from 0 to 59, that represent the second.

n* is zero to seven digits, ranging from 0 to 9999999, that represent the fractional seconds.

Character length

8 positions minimum (hh:mm:ss) to 16 maximum (hh:mm:ss.nnnnnnn)

Precision, scale

(user specifies scale only)

Specified scale	Result (precision, scale)	Column length (bytes)	Fractional seconds precision
time	(16,7)	5	7
time(0)	(8,0)	3	0-2
time(1)	(10,1)	3	0-2
time(2)	(11,2)	3	0-2
time(3)	(12,3)	4	3-4
time(4)	(13,4)	4	3-4
time(5)	(14,5)	5	5-7
time(6)	(15,6)	5	5-7
time(7)	(16,7)	5	5-7

Storage size

5 bytes, fixed, is the default with the default of 100ns fractional second precision.

Accuracy

100 nanoseconds

Default value

00:00:00

This value is used for the appended time part for implicit conversion from date to datetime2 or datetimeoffset.

User-defined fractional second precision

Yes

Time zone offset aware and preservation

Daylight saving aware

Supported String Literal Formats for time

The following table shows the valid string literal formats for the time data type.

SQL Server	Description
hh:mm[:ss][:fractional seconds][AM][PM] hh:mm[:ss][.fractional seconds][AM][PM] hhAM[PM] hh AM[PM]	The hour value of 0 represents the hour after midnight (AM), regardless of whether AM is specified. PM cannot be specified when the hour equals 0. Hour values from 01 through 11 represent the hours before noon if neither AM nor PM is specified. The values represent the hours before noon when AM is specified. The values represent hours after noon if PM is specified. The hour value 12 represents the hour that starts at noon if neither AM nor PM is specified. If AM is specified, the value represents the hour that starts at midnight. If PM is specified, the value represents the hour that starts at noon. For example, 12:01 is 1 minute after noon, as is 12:01 PM; and 12:01 AM is one minute after midnight. Specifying 12:01 AM is the same as specifying 00:01 or 00:01 AM. Hour values from 13 through 23 represent hours after noon if AM or PM is not specified. The values also represent the hours after noon when PM is specified. AM cannot be specified when the hour value is from 13 through 23. An hour value of 24 is not valid. To represent midnight, use 12:00 AM or 00:00. Milliseconds can be preceded by either a colon (:) or a period (.). If a colon is used, the number means thousandths-of-a-second. If a period is used, a single digit means tenths-of-a-second, two digits mean hundredths-of-a-second, and three digits mean thousandths-of-a-second. For example, 12:30:20:1 indicates 20 and one-thousandth seconds past 12:30; 12:30:20.1 indicates 20 and one-tenth seconds past 12:30.

hh:mm[:ss][:fractional seconds][AM][PM]

hh:mm[:ss][.fractional seconds][AM][PM]

hhAM[PM]

hh AM[PM]

The hour value of 0 represents the hour after midnight (AM), regardless of whether AM is specified. PM cannot be specified when the hour equals 0.

Hour values from 01 through 11 represent the hours before noon if neither AM nor PM is specified. The values represent the hours before noon when AM is specified. The values represent hours after noon if PM is specified.

The hour value 12 represents the hour that starts at noon if neither AM nor PM is specified. If AM is specified, the value represents the hour that starts at midnight. If PM is specified, the value represents the hour that starts at noon. For example, 12:01 is 1 minute after noon, as is 12:01 PM; and 12:01 AM is one minute after midnight. Specifying 12:01 AM is the same as specifying 00:01 or 00:01 AM.

Hour values from 13 through 23 represent hours after noon if AM or PM is not specified. The values also represent the hours after noon when PM is specified. AM cannot be specified when the hour value is from 13 through 23.

An hour value of 24 is not valid. To represent midnight, use 12:00 AM or 00:00.

Milliseconds can be preceded by either a colon (:) or a period (.). If a colon is used, the number means thousandths-of-a-second. If a period is used, a single digit means tenths-of-a-second, two digits mean hundredths-of-a-second, and three digits mean thousandths-of-a-second. For example, 12:30:20:1 indicates 20 and one-thousandth seconds past 12:30; 12:30:20.1 indicates 20 and one-tenth seconds past 12:30.

ISO 8601	Notes
hh:mm:ss hh:mm[:ss][.fractional seconds]	hh is two digits, ranging from 0 to 14, that represent the number of hours in the time zone offset. mm is two digits, ranging from 0 to 59, that represent the number of additional minutes in the time zone offset.

hh:mm:ss

hh:mm[:ss][.fractional seconds]

hh is two digits, ranging from 0 to 14, that represent the number of hours in the time zone offset.
mm is two digits, ranging from 0 to 59, that represent the number of additional minutes in the time zone offset.

ODBC	Notes
{t 'hh:mm:ss[.fractional seconds]'}	ODBC API specific. Functions in SQL Server 2012 as in SQL Server 2005.

{t 'hh:mm:ss[.fractional seconds]'}

ODBC API specific.

Functions in SQL Server 2012 as in SQL Server 2005.

Compliance with ANSI and ISO 8601 Standards

Using hour 24 to represent midnight and leap second over 59 as defined by ISO 8601 (5.3.2 and 5.3) are not supported to be backward compatible and consistent with the existing date and time types.

The default string literal format (used for down-level client) will align with the SQL standard form, which is defined as hh:mm:ss[.nnnnnnn]. This format resembles the ISO 8601 definition for TIME excluding fractional seconds.

Backward Compatibility for Down-level Clients

Some down-level clients do not support the time, date, datetime2 and datetimeoffset data types. The following table shows the type mapping between an up-level instance of SQL Server and down-level clients.

SQL Server 2012 data type	Default string literal format passed to down-level client	Down-level ODBC	Down-level OLEDB	Down-level JDBC	Down-level SQLCLIENT
time	hh:mm:ss[.nnnnnnn]	SQL_WVARCHAR or SQL_VARCHAR	DBTYPE_WSTRor DBTYPE_STR	Java.sql.String	String or SqString
date	YYYY-MM-DD	SQL_WVARCHAR or SQL_VARCHAR	DBTYPE_WSTRor DBTYPE_STR	Java.sql.String	String or SqString
datetime2	YYYY-MM-DD hh:mm:ss[.nnnnnnn]	SQL_WVARCHAR or SQL_VARCHAR	DBTYPE_WSTRor DBTYPE_STR	Java.sql.String	String or SqString
datetimeoffset	YYYY-MM-DD hh:mm:ss[.nnnnnnn] [+\|-]hh:mm	SQL_WVARCHAR or SQL_VARCHAR	DBTYPE_WSTRor DBTYPE_STR	Java.sql.String	String or SqString

Converting Date and Time Data

When you convert to date and time data types, SQL Server rejects all values it cannot recognize as dates or times. For information about using the CAST and CONVERT functions with date and time data, see CAST and CONVERT (Transact-SQL)

Converting time(n) Data Type to Other Date and Time Types

The following table describes what occurs when a time data type is converted to other date and time data types.

Data type to convert to	Conversion details
time(n)	The hour, minute, and seconds are copied. When the destination precision is less than the source precision, the fractional seconds will be rounded up to fit the destination precision. The following example shows the results of converting a time(4) value to a time(3) value. `DECLARE @timeFrom time(4) = '12:34:54.1237'; DECLARE @timeTo time(3) = @timeFrom; SELECT @timeTo AS 'time(3)', @timeFrom AS 'time(4)'; --Results --time(3) time(4) -------------- ------------- --12:34:54.124 12:34:54.1237 -- --(1 row(s) affected)`
date	The conversion fails, and error message 206 is raised: "Operand type clash: date is incompatible with time".
datetime	The hour, minute, and second values are copied; and the date component is set to '1900-01-01'. When the fractional seconds precision of the time(n) value is greater than three digits, the datetime result will be truncated. The following code shows the results of converting a time(4) value to a datetime value. `DECLARE @time time(4) = '12:15:04.1237'; DECLARE @datetime datetime= @time; SELECT @time AS '@time', @datetime AS '@datetime'; --Result --@time @datetime --------------- ----------------------- --12:15:04.1237 1900-01-01 12:15:04.123 -- --(1 row(s) affected)`
smalldatetime	The date is set to '1900-01-01', and the hour and minute values are rounded up. The seconds and fractional seconds are set to 0. The following code shows the results of converting a time(4) value to a smalldatetime value. -- Shows rounding up of the minute value. DECLARE @time time(4) = '12:15:59.9999'; DECLARE @smalldatetime smalldatetime= @time; SELECT @time AS '@time', @smalldatetime AS '@smalldatetime'; --Result @time @smalldatetime ---------------- ----------------------- 12:15:59.9999 1900-01-01 12:16:00-- --(1 row(s) affected) -- Shows rounding up of the hour value. DECLARE @time time(4) = '12:59:59.9999'; DECLARE @smalldatetime smalldatetime= @time; SELECT @time AS '@time', @smalldatetime AS '@smalldatetime'; @time @smalldatetime ---------------- ----------------------- 12:59:59.9999 1900-01-01 13:00:00 (1 row(s) affected)
datetimeoffset(n)	The date is set to '1900-01-01', and the time is copied. The time zone offset is set to +00:00. When the fractional seconds precision of the time(n) value is greater than the precision of the datetimeoffset(n) value, the value is rounded up to fit. The following example shows the results of converting a time(4) value to a datetimeoffset(3) type. `DECLARE @time time(4) = '12:15:04.1237'; DECLARE @datetimeoffset datetimeoffset(3) = @time; SELECT @time AS '@time', @datetimeoffset AS '@datetimeoffset'; --Result --@time @datetimeoffset --------------- ------------------------------ --12:15:04.1237 1900-01-01 12:15:04.124 +00:00 -- --(1 row(s) affected)`
datetime2(n)	The date is set to '1900-01-01', the time component is copied, and the time zone offset is set to 00:00. When the fractional seconds precision of the datetime2(n) value is greater than the time(n) value, the value will be rounded up to fit. The following example shows the results of converting a time(4) value to a datetime2(2) value. `DECLARE @time time(4) = '12:15:04.1237'; DECLARE @datetime2 datetime2(3) = @time; SELECT @datetime2 AS '@datetime2', @time AS '@time'; --Result --@datetime2 @time ------------------------- ------------- --1900-01-01 12:15:04.124 12:15:04.1237 -- --(1 row(s) affected)`

Converting String Literals to time(n)

Conversions from string literals to date and time types are permitted if all parts of the strings are in valid formats. Otherwise, a runtime error is raised. Implicit conversions or explicit conversions that do not specify a style, from date and time types to string literals will be in the default format of the current session. The following table shows the rules for converting a string literal to the time data type.

Input string literal	Conversion Rule
ODBC DATE	ODBC string literals are mapped to the datetime data type. Any assignment operation from ODBC DATETIME literals into timetypes will cause an implicit conversion between datetime and this type as defined by the conversion rules.
ODBC TIME	See ODBC DATE rule above.
ODBC DATETIME	See ODBC DATE rule above.
DATE only	Default values are supplied.
TIME only	Trivial
TIMEZONE only	Default values are supplied.
DATE + TIME	The TIME part of the input string is used.
DATE + TIMEZONE	Not allowed.
TIME + TIMEZONE	The TIME part of the input string is used.
DATE + TIME + TIMEZONE	The TIME part of local DATETIME will be used.

Examples

A. Comparing date and time Data Types

The following example compares the results of casting a string to each date and time data type.

SELECT 
     CAST('2007-05-08 12:35:29. 1234567 +12:15' AS time(7)) AS 'time' 
    ,CAST('2007-05-08 12:35:29. 1234567 +12:15' AS date) AS 'date' 
    ,CAST('2007-05-08 12:35:29.123' AS smalldatetime) AS 
        'smalldatetime' 
    ,CAST('2007-05-08 12:35:29.123' AS datetime) AS 'datetime' 
    ,CAST('2007-05-08 12:35:29. 1234567 +12:15' AS datetime2(7)) AS 
        'datetime2'
    ,CAST('2007-05-08 12:35:29.1234567 +12:15' AS datetimeoffset(7)) AS 
        'datetimeoffset';

Data type	Output
time	12:35:29. 1234567
date	2007-05-08
smalldatetime	2007-05-08 12:35:00
datetime	2007-05-08 12:35:29.123
datetime2	2007-05-08 12:35:29. 1234567
datetimeoffset	2007-05-08 12:35:29.1234567 +12:15

B. Inserting Valid Time String Literals into a time(7) Column

The following table lists different string literals that can be inserted into a column of data type time(7) with the values that are then stored in that column.

String literal format type	Inserted string literal	time(7) value that is stored	Description
SQL Server	'01:01:01:123AM'	01:01:01.1230000	When a colon (:) comes before fractional seconds precision, scale cannot exceed three positions or an error will be raised.
SQL Server	'01:01:01.1234567 AM'	01:01:01.1234567	When AM or PM is specified, the time is stored in 24-hour format without the literal AM or PM
SQL Server	'01:01:01.1234567 PM'	13:01:01.1234567	When AM or PM is specified, the time is stored in 24-hour format without the literal AM or PM
SQL Server	'01:01:01.1234567PM'	13:01:01.1234567	A space before AM or PM is optional.
SQL Server	'01AM'	01:00:00.0000000	When only the hour is specified, all other values are 0.
SQL Server	'01 AM'	01:00:00.0000000	A space before AM or PM is optional.
SQL Server	'01:01:01'	01:01:01.0000000	When fractional seconds precision is not specified, each position that is defined by the data type is 0.
ISO 8601	'01:01:01.1234567'	01:01:01.1234567	To comply with ISO 8601, use 24-hour format, not AM or PM.
ISO 8601	'01:01:01.1234567 +01:01'	01:01:01.1234567	The optional time zone difference (TZD) is allowed in the input but is not stored.

C. Inserting Time String Literal into Columns of Each date and time Date Type

In the following table the first column shows a time string literal to be inserted into a database table column of the date or time data type shown in the second column. The third column shows the value that will be stored in the database table column.

Inserted string literal	Column data type	Value that is stored in column	Description
'12:12:12.1234567'	time(7)	12:12:12.1234567	If the fractional seconds precision exceeds the value specified for the column, the string will be truncated without error.
'2007-05-07'	date	NULL	Any time value will cause the INSERT statement to fail.
'12:12:12'	smalldatetime	1900-01-01 12:12:00	Any fractional seconds precision value will cause the INSERT statement to fail.
'12:12:12.123'	datetime	1900-01-01 12:12:12.123	Any second precision longer than three positions will cause the INSERT statement to fail.
'12:12:12.1234567'	datetime2(7)	1900-01-01 12:12:12.1234567	If the fractional seconds precision exceeds the value specified for the column, the string will be truncated without error.
'12:12:12.1234567'	datetimeoffset(7)	1900-01-01 12:12:12.1234567 +00:00	If the fractional seconds precision exceeds the value specified for the column, the string will be truncated without error.

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