datetime2 (Transact-SQL)

**APPLIES TO:** SQL Server (starting with 2008) Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse

Defines a date that is combined with a time of day that is based on 24-hour clock. datetime2 can be considered as an extension of the existing datetime type that has a larger date range, a larger default fractional precision, and optional user-specified precision.

datetime2 description

For data type metadata, see sys.systypes (Transact-SQL) or TYPEPROPERTY (Transact-SQL). Precision and scale are variable for some date and time data types. To obtain the precision and scale for a column, see COLUMNPROPERTY (Transact-SQL), COL_LENGTH (Transact-SQL), or sys.columns (Transact-SQL).

Supported string literal formats for datetime2

The following tables list the supported ISO 8601 and ODBC string literal formats for datetime2. For information about alphabetical, numeric, unseparated, and time formats for the date and time parts of datetime2, see date (Transact-SQL) and time (Transact-SQL).

ANSI and ISO 8601 compliance

The ANSI and ISO 8601 compliance of date and time apply to datetime2.

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.

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 other date and time types to the datetime2 data type

This section describes what occurs when other date and time data types are converted to the datetime2 data type.

When the conversion is from date, the year, month and day are copied. The time component is set to 00:00:00.0000000. The following code shows the results of converting a date value to a datetime2 value.

DECLARE @date date = '12-21-16';
DECLARE @datetime2 datetime2 = @date;

SELECT @datetime2 AS '@datetime2', @date AS '@date';
  
--Result  
--@datetime2                  @date
----------------------------- ----------
--2016-12-21 00:00:00.0000000 2016-12-21

When the conversion is from time(n), the time component is copied, and the date component is set to ‘1900-01-01’. The following example shows the results of converting a time(7) value to a datetime2 value.

DECLARE @time time(7) = '12:10:16.1234567';
DECLARE @datetime2 datetime2 = @time;

SELECT @datetime2 AS '@datetime2', @time AS '@time';
  
--Result  
--@datetime2                  @time
----------------------------- ----------------
--1900-01-01 12:10:16.1234567 12:10:16.1234567

When the conversion is from smalldatetime, the hours and minutes are copied. The seconds and fractional seconds are set to 0. The following code shows the results of converting a smalldatetime value to a datetime2 value.

DECLARE @smalldatetime smalldatetime = '12-01-16 12:32';
DECLARE @datetime2 datetime2 = @smalldatetime;

SELECT @datetime2 AS '@datetime2', @smalldatetime AS '@smalldatetime'; 
  
--Result  
--@datetime2                  @smalldatetime
----------------------------- -----------------------
--2016-12-01 12:32:00.0000000 2016-12-01 12:32:00 

When the conversion is from datetimeoffset(n), the date and time components are copied. The time zone is truncated. The following example shows the results of converting a datetimeoffset(7) value to a datetime2 value.

DECLARE @datetimeoffset datetimeoffset(7) = '2016-10-23 12:45:37.1234567 +10:0';
DECLARE @datetime2 datetime2 = @datetimeoffset;

SELECT @datetime2 AS '@datetime2', @datetimeoffset AS '@datetimeoffset'; 
  
--Result  
--@datetime2                  @datetimeoffset
----------------------------- ----------------------------------
--2016-10-23 12:45:37.1234567 2016-10-23 12:45:37.1234567 +10:00

When the conversion is from datetime, the date and time are copied. The fractional precision is extended to 7 digits. The following example shows the results of converting a datetime value to a datetime2 value.

DECLARE @datetime datetime = '2016-10-23 12:45:37.333';
DECLARE @datetime2 datetime2 = @datetime;

SELECT @datetime2 AS '@datetime2', @datetime AS '@datetime';
   
--Result  
--@datetime2                  @datetime
------------------------- ---------------------------
--2016-10-23 12:45:37.3333333 2016-10-23 12:45:37.333

[!NOTE] Under database compatibility level 130, implicit conversions from datetime to datetime2 data types show improved accuracy by accounting for the fractional milliseconds, resulting in different converted values, as seen in the example above. Use explicit casting to datetime2 datatype whenever a mixed comparison scenario between datetime and datetime2 datatypes exists. For more information, refer to this Microsoft Support Article.

Converting String Literals to datetime2

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 datetime2 data type.

Examples

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';  

Here is the result set.

See also

CAST and CONVERT (Transact-SQL)