阅读导航
数据库日期和时间类型
相互转换
time ⇌ date
time ⇌ smalldatetime
time ⇌ datetime
time ⇌ datetime2
time ⇌ datetimeoffset
date ⇌ smalldatetime
date ⇌ datetime
date ⇌ datetime2
date ⇌ datetimeoffset
smalldatetime ⇌ datetime
smalldatetime ⇌ datetime2
smalldatetime ⇌ datetimeoffset
datetime ⇌ datetime2
datetime ⇌ datetimeoffset
datetime2 ⇌ datetimeoffset
数据库日期和时间类型:
类型 | 格式 | 范围 |
---|---|---|
time | hh:mm:ss[.nnnnnnn] | 00:00:00.0000000 ~ 23:59:59.9999999 |
date | YYYY-MM-DD | 0001-01-01 ~ 9999-12-31 |
smalldatetime | YYYY-MM-DD hh:mm:ss | 1900-01-01 ~ 079-06-06 |
datetime | YYYY-MM-DD hh:mm:ss[.nnn] | 1753-01-01 ~ 99-12-31 |
datetime2 | YYYY-MM-DD hh:mm:ss[.nnnnnnn] | 0001-01-01 00:00:00.0000000 ~ 99-12-31 23:59:59.9999999 |
datetimeoffset | YYYY-MM-DD hh:mm:ss[.nnnnnnn] [+|-]hh:mm | 0001-01-01 00:00:00.0000000 ~9999-12-31 23:59:59.9999999 (in UTC) |
相互转换(SET DATEFORMAT dmy;)
time ⇌ date
1: -- time -> date
2: DECLARE @time time(4) = '12:15:04.1234';
3: DECLARE @date date= @time;
4:
5: SELECT @time AS '@time', @date AS '@date';
Result:
Operand type clash: time is incompatible with date
1: -- date -> time
2: DECLARE @date date= '12-10-25';
3: DECLARE @time time= @date;
4:
5: SELECT @date AS '@date', @time AS '@time';
Result:
Operand type clash: time is incompatible with date
time ⇌ smalldatetime
1: -- time -> smalldatetime
2: DECLARE @time time(4) = '12:15:04.1234';
3: DECLARE @smalldatetime smalldatetime= @time;
4:
5: SELECT @time AS '@time', @smalldatetime AS '@smalldatetime';
Result:
@time @smalldatetime 12:15:04.1234 1900-01-01 12:15:00
1: -- samlldatetime –> time
2: DECLARE @smalldatetime smalldatetime = '13-12-1995 12:43:10';
3: DECLARE @time time(4) = @smalldatetime;
4:
5: SELECT @smalldatetime AS '@smalldatetime', @time AS 'time';
Result:
@smalldatetime @time 1995-12-13 12:43:00 12:43:00.0000
time ⇌ datetime
1: -- time -> datetime
2: DECLARE @time time(4) = '12:10:05.1234';
3: DECLARE @datetime datetime = @time;
4:
5: SELECT @time AS '@datetime', @datetime AS '@time';
Result:
@time @datetime 12:10:05.1234 1900-01-01 12:10:05.123
1: -- datetime -> time
2: DECLARE @datetime datetime = '12-11-05 12:10:05.123';
3: DECLARE @time time(4) = @datetime;
4:
5: SELECT @datetime AS '@datetime', @time AS '@time';
Result:
@datetime @time 2005-11-12 12:10:05.123 12:10:05.1230
time ⇌ datetime2
----
1: -- time -> datetime2
2: DECLARE @time time(4) = '12:15:04.1234';
3: DECLARE @datetime2 datetime2(3) = @time;
4:
5: SELECT @datetime2 AS '@datetime2', @time AS '@time';
Result:
@time @datetime2 12:15:04.1234 1900-01-01 12:15:04.123
1: -- datetime2 -> time
2: DECLARE @datetime2 datetime2(4) = '12-10-25 12:32:10.1234';
3: DECLARE @time time(3) = @datetime2;
4:
5: SELECT @datetime2 AS '@datetime2', @time AS '@time(3)';
Result:
@datetime2 @time(3) 2025-10-12 12:32:10.1234 12:32:10.123
time ⇌ datetimeoffset
1: -- time -> datetimeoffset
2: DECLARE @time time(4) = '12:15:04.1234';
3: DECLARE @datetimeoffset datetimeoffset(3) = @time;
4:
5: SELECT @time AS '@time', @datetimeoffset AS '@datetimeoffset';
Result:
@time @datetimeoffset 12:15:04.1234 1900-01-01 12:15:04.123 +00:00
1: -- datetimeoffset -> time
2: DECLARE @datetimeoffset datetimeoffset(4) = '12-10-25 12:32:10.1234 +01:0';
3: DECLARE @time time(3) = @datetimeoffset;
4:
5: SELECT @datetimeoffset AS '@datetimeoffset ', @time AS '@time';
Result:
@datetimeoffset @time 2025-10-12 12:32:10.1234 +01:00 12:32:10.123
date ⇌ smalldatetime
1: -- date -> smalldatetime
2: DECLARE @date date= '1912-10-25';
3: DECLARE @smalldatetime smalldatetime = @date;
4:
5: SELECT @date AS '@date', @smalldatetime AS '@smalldatetime';
Result:
@date @smalldatetime 1912-10-25 1912-10-25 00:00:00
1: -- smalldatetime -> date
2: DECLARE @smalldatetime smalldatetime = '13-12-1955 12:43:10';
3: DECLARE @date date = @smalldatetime
4:
5: SELECT @smalldatetime AS '@smalldatetime', @date AS '@date';
Result:
@smalldatetime @date 1955-12-13 12:43:00 1955-12-13
date ⇌ datetime
1: -- date -> datetime
2: DECLARE @date date= '12-10-25';
3: DECLARE @datetime datetime= @date;
4:
5: SELECT @date AS '@date', @datetime AS '@datetime';
Result:
@date @datetime 2025-10-12 2025-10-12 00:00:00.000
1: -- datetime -> date
2: DECLARE @datetime datetime = '12-11-05 12:43:10';
3: DECLARE @date date = @datetime;
4:
5: SELECT @datetime AS '@datetime', @date AS '@date';
Result:
@datetime @date 2005-11-12 12:43:10.000 2005-11-12
date ⇌ datetime2
1: -- date -> datetime2
2: DECLARE @date date = '25-10-2030'
3: DECLARE @datetime2 datetime2(3) = @date;
4:
5: SELECT @date AS '@date', @datetime2 AS '@datetime2(3)';
Result:
@date @datetime2(3) 2030-10-25 2030-10-25 00:00:00.000
1: -- datetime2 -> date
2: DECLARE @datetime2 datetime2(4) = '12-10-25 12:32:10.1234';
3: DECLARE @date date = @datetime2;
4:
5: SELECT @datetime2 AS '@datetime2', @date AS '@date';
Result:
@datetime2 @date 2025-10-12 12:32:10.1234 2025-10-12
date ⇌ datetimeoffset
1: -- date -> datetimeoffset
2: DECLARE @date date = '1912-10-25';
3: DECLARE @datetimeoffset datetimeoffset(3) = @date;
4:
5: SELECT @date AS '@date', @datetimeoffset AS '@datetimeoffset';
Result:
@date @datetimeoffset 1912-10-25 1912-10-25 00:00:00.000 +00:00
1: -- datetimeoffset -> date
2: DECLARE @datetimeoffset datetimeoffset(4) = '12-10-25 12:32:10 +01:0';
3: DECLARE @date date= @datetimeoffset;
4:
5: SELECT @datetimeoffset AS '@datetimeoffset ', @date AS '@date';
Result:
@datetimeoffset @date 2025-10-12 12:32:10.0000 +01:00 2025-10-12
smalldatetime ⇌ datetime
1: -- smalldatetime -> datetime
2: DECLARE @smalldatetime smalldatetime = '12-10-2040 12:43:10';
3: DECLARE @datetime datetime = @smalldatetime;
4:
5: SELECT @smalldatetime AS '@smalldatetime', @datetime AS '@datetime';
Result:
@smalldatetime @datetime 2040-10-12 12:43:00 2040-10-12 12:43:00.000
1: -- datetime -> smalldatetime
2: DECLARE @datetime datetime = '12-11-05 12:43:10.123';
3: DECLARE @smalldatetime smalldatetime = @datetime;
4:
5: SELECT @datetime AS 'datetime', @smalldatetime AS '@smalldatetime';
Result:
datetime @smalldatetime 2005-11-12 12:43:10.123 2005-11-12 12:43:00
smalldatetime ⇌ datetime2
1: -- smalldatetime -> datetime2
2: DECLARE @smalldatetime smalldatetime = '12-06-2011 12:43:10';
3: DECLARE @datetime2 datetime2(4) = @smalldatetime;
4:
5: SELECT @smalldatetime AS '@smalldatetime', @datetime2 AS '@datetime2(4)';
Result:
@smalldatetime @datetime2(4) 2011-06-12 12:43:00 2011-06-12 12:43:00.0000
1: -- datetime2 -> smalldatetime
2: DECLARE @datetime2 datetime2 = '12-10-25 12:32:10.1234567';
3: DECLARE @smalldatetime smalldatetime = @datetime2;
4:
5: SELECT @datetime2 AS '@datetime2', @smalldatetime AS '@smalldatetime';
Result:
@datetime2 @smalldatetime 2025-10-12 12:32:10.1234567 2025-10-12 12:32:00
smalldatetime ⇌ datetimeoffset
1: -- samlldatetime -> datetimeoffset
2: DECLARE @smalldatetime smalldatetime = '12-10-2013 12:43:10';
3: DECLARE @datetimeoffset datetimeoffset(4) = @smalldatetime;
4:
5: SELECT @smalldatetime AS '@smalldatetime', @datetimeoffset AS '@datetimeoffset(4)';
Result:
@smalldatetime @datetimeoffset(4) 2013-10-12 12:43:00 2013-10-12 12:43:00.0000 +00:00
1: -- datetimeoffset -> smalldatetime
2: DECLARE @datetimeoffset datetimeoffset(3) = '1912-10-25 12:24:32 +10:0';
3: DECLARE @smalldatetime smalldatetime = @datetimeoffset;
4:
5: SELECT @datetimeoffset AS '@datetimeoffset', @smalldatetime AS '@smalldatetime';
Result:
@datetimeoffset @smalldatetime 1912-10-25 12:24:32.000 +10:00 1912-10-25 12:25:00
datetime ⇌ datetime2
1: -- datetimes -> datetime2
2: DECLARE @datetime datetime = '10-10-2014 12:45:37.123';
3: DECLARE @datetime2 datetime2(4) = @datetime;
4:
5: SELECT @datetime AS '@datetime', @datetime2 AS '@datetime2'
Result:
@datetime @datetime2 2014-10-10 12:45:37.123 2014-10-10 12:45:37.1230
1: -- datetimes2 -> datetime
2: DECLARE @datetime2 datetime2(4) = '1968-10-23 12:45:37.1237';
3: DECLARE @datetime datetime = @datetime2;
4:
5: SELECT @datetime2 AS '@datetime2', @datetime AS '@datetime';
Result:
@datetime2 @datetime 1968-10-23 12:45:37.1237 1968-10-23 12:45:37.123
datetime ⇌ datetimeoffset
1: -- datetime -> datetimeoffset
2: DECLARE @datetime datetime = '12-10-25 12:32:10.123';
3: DECLARE @datetimeoffset datetimeoffset = @datetime;
4:
5: SELECT @datetime AS '@datetime ', @datetimeoffset AS '@datetimeoffset';
Result:
@datetime @datetimeoffset 2025-10-12 12:32:10.123 2025-10-12 12:32:10.1230000 +00:00
1: -- datetimeoffset -> datetime
2: DECLARE @datetimeoffset datetimeoffset(4) = '12-10-25 12:32:10.1234 +01:0';
3: DECLARE @datetime datetime = @datetimeoffset;
4:
5: SELECT @datetimeoffset AS '@datetimeoffset ', @datetime AS '@datetime';
Result:
@datetimeoffset @datetime 2025-10-12 12:32:10.1234 +01:00 2025-10-12 12:32:10.123
datetime2 ⇌ datetimeoffset
1: -- datetime2 -> datetimeoffset
2: DECLARE @datetime2 datetime2(3) = '12-10-25 12:32:10.1234567';
3: DECLARE @datetimeoffset datetimeoffset(2) = @datetime2;
4:
5: SELECT @datetime2 AS '@datetime2', @datetimeoffset AS '@datetimeoffset(2)';
Result:
@datetime2 @datetimeoffset(2) 2025-10-12 12:32:10.123 2025-10-12 12:32:10.12 +00:00
1: -- datetimeoffset -> datetime2
2: DECLARE @datetimeoffset datetimeoffset(4) = '1912-10-25 12:24:32.1234 +10:0';
3: DECLARE @datetime2 datetime2(3)= @datetimeoffset;
4:
5: SELECT @datetimeoffset AS '@datetimeoffset', @datetime2 AS '@datetime2';
Result:
@datetimeoffset @datetime2 1912-10-25 12:24:32.1234 +10:00 1912-10-25 12:24:32.123