[sql] How to combine date from one field with time from another field - MS SQL Server

In an extract I am dealing with, I have 2 datetime columns. One column stores the dates and another the times as shown.

How can I query the table to combine these two fields into 1 column of type datetime?

Dates

2009-03-12 00:00:00.000
2009-03-26 00:00:00.000
2009-03-26 00:00:00.000

Times

1899-12-30 12:30:00.000
1899-12-30 10:00:00.000
1899-12-30 10:00:00.000

This worked for me

CAST(Tbl.date as DATETIME) + CAST(Tbl.TimeFrom AS TIME)

(on SQL 2008 R2)

If the time element of your date column and the date element of your time column are both zero then Lieven's answer is what you need. If you can't guarantee that will always be the case then it becomes slightly more complicated:

SELECT DATEADD(day, 0, DATEDIFF(day, 0, your_date_column)) +
    DATEADD(day, 0 - DATEDIFF(day, 0, your_time_column), your_time_column)
FROM your_table

DECLARE @Dates table ([Date] datetime);
DECLARE @Times table ([Time] datetime);

INSERT INTO @Dates VALUES('2009-03-12 00:00:00.000');
INSERT INTO @Dates VALUES('2009-03-26 00:00:00.000');
INSERT INTO @Dates VALUES('2009-03-30 00:00:00.000');

INSERT INTO @Times VALUES('1899-12-30 12:30:00.000');
INSERT INTO @Times VALUES('1899-12-30 10:00:00.000');
INSERT INTO @Times VALUES('1899-12-30 10:00:00.000');

WITH Dates (ID, [Date])
AS (
    SELECT ROW_NUMBER() OVER (ORDER BY [Date]), [Date] FROM @Dates
), Times (ID, [Time])
AS (
    SELECT ROW_NUMBER() OVER (ORDER BY [Time]), [Time] FROM @Times
)
SELECT Dates.[Date] + Times.[Time] FROM Dates
    JOIN Times ON Times.ID = Dates.ID

Prints:

2009-03-12 10:00:00.000
2009-03-26 10:00:00.000
2009-03-30 12:30:00.000

Convert both field into DATETIME :

SELECT CAST(@DateField as DATETIME) + CAST(@TimeField AS DATETIME)

and if you're using Getdate() use this first:

DECLARE @FechaActual DATETIME = CONVERT(DATE, GETDATE());
SELECT CAST(@FechaActual as DATETIME) + CAST(@HoraInicioTurno AS DATETIME)

This is an alternative solution without any char conversions:

DATEADD(ms, DATEDIFF(ms, '00:00:00', [Time]), CONVERT(DATETIME, [Date]))

You will only get milliseconds accuracy this way, but that would normally be OK. I have tested this in SQL Server 2008.

If you're not using SQL Server 2008 (i.e. you only have a DateTime data type), you can use the following (admittedly rough and ready) TSQL to achieve what you want:

DECLARE @DateOnly AS datetime
DECLARE @TimeOnly AS datetime 

SET @DateOnly = '07 aug 2009 00:00:00'
SET @TimeOnly = '01 jan 1899 10:11:23'


-- Gives Date Only.
SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, @DateOnly))

-- Gives Time Only.
SELECT DATEADD(Day, -DATEDIFF(Day, 0, @TimeOnly), @TimeOnly)

-- Concatenates Date and Time parts.
SELECT
CAST(
    DATEADD(dd, 0, DATEDIFF(dd, 0, @DateOnly)) + ' ' +
    DATEADD(Day, -DATEDIFF(Day, 0, @TimeOnly), @TimeOnly)           
as datetime)

It's rough and ready, but it works!

SELECT CAST(CAST(@DateField As Date) As DateTime) + CAST(CAST(@TimeField As Time) As DateTime)

SELECT CAST(your_date_column AS date) + CAST(your_time_column AS datetime) FROM your_table

Works like a charm

I ran into similar situation where I had to merge Date and Time fields to DateTime field. None of the above mentioned solution work, specially adding two fields as the data type for addition of these 2 fields is not same.

I created below solution, where I added hour and then minute part to the date. This worked beautifully for me. Please check it out and do let me know if you get into any issues.

;with tbl as ( select StatusTime = '12/30/1899 5:17:00 PM', StatusDate = '7/24/2019 12:00:00 AM' ) select DATEADD(MI, DATEPART(MINUTE,CAST(tbl.StatusTime AS TIME)),DATEADD(HH, DATEPART(HOUR,CAST(tbl.StatusTime AS TIME)), CAST(tbl.StatusDate as DATETIME))) from tbl

Result: 2019-07-24 17:17:00.000

select s.SalesID from SalesTbl s 
        where cast(cast(s.SaleDate  as date) as datetime) + cast(cast(s.SaleCreatedDate as time) as datetime)  

between @FromDate and @ToDate

simply concatenate both , but cast them first as below

select cast(concat(Cast(DateField as varchar), ' ', Cast(TimeField as varchar)) as datetime) as DateWithTime from TableName;

Another way is to use CONCATand CAST, be aware, that you need to use DATETIME2(x) to make it work. You can set x to anything between 0-7 7 meaning no precision loss.

DECLARE @date date = '2018-03-12'
DECLARE @time time = '07:00:00.0000000'
SELECT CAST(CONCAT(@date, ' ', @time) AS DATETIME2(7))

Returns 2018-03-12 07:00:00.0000000

Tested on SQL Server 14

To combine date from a datetime column and time from another datetime column this is the best fastest solution for you:

select cast(cast(DateColumn as date) as datetime) + cast(TimeColumn as datetime) from YourTable

1. If both of your fields are datetime then simply adding those will work.

   eg:

   Declare @d datetime, @t datetime
   set @d = '2009-03-12 00:00:00.000';
   set @t = '1899-12-30 12:30:00.000';
   select @d + @t
   

2. If you used Date & Time datatype then just cast the time to datetime

   eg:

   Declare @d date, @t time
   set @d = '2009-03-12';
   set @t = '12:30:00.000';
   select @d + cast(@t as datetime)
   

Convert the first date stored in a datetime field to a string, then convert the time stored in a datetime field to string, append the two and convert back to a datetime field all using known conversion formats.

Convert(datetime, Convert(char(10), MYDATETIMEFIELD, 103) + ' ' + Convert(char(8), MYTIMEFIELD, 108), 103) 

I had many errors as stated above so I did it like this

try_parse(concat(convert(date,Arrival_date),' ',arrival_time) as datetime) AS ArrivalDateTime

It worked for me.