T-SQL – How to Extract Date from Datetime in SQL Server 2005

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I am running a select against a datetime column in SQL Server 2005. I can select only the date from this datetime column?

Best Answer

Best way is:

   SELECT DATEADD(day, DATEDIFF(Day, 0, @ADate), 0)

This is because internally, SQL Server stores all dates as two integers, of which the first one is the ****number of days*** since 1 Jan 1900. (the second one is the time portion, stored as the number of seconds since Midnight. (seconds for SmallDateTimes, or milleseconds for DateTimes)
Using the above expression is better because it avoids all conversions, directly reading and accessing that first integer in a dates internal representation without having to perform any processing... the two zeroes in the above expression (which represent 1 Jan 1900), are also directly utilized w/o processing or conversion, because they match the SQL server internal representation of the date 1 jan 1900 exactly as presented (as an integer)..

*NOTE. Actually, the number of date boundaries (midnights) you have to cross to get from the one date to the other.

Related Solutions

SQL Server DateTime – How to Return Only the Date

NOTE: This answer returns the original DATETIME or DATETIME2 type. For an expression that returns a true DATE type (SQL Server 2008 and later), see BenR's answer below.

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, @your_date))

for example

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, GETDATE()))

gives me

2008-09-22 00:00:00.000

Pros:

No varchar<->datetime conversions required
No need to think about locale

SQL – How to Get Date from Datetime in SQL Server

The reason why your query doesn't return the row you expect, is because GETDATE() returns the date and time portion at the moment the query was executed. The value in your DateCreated column will not match the time portion, so no rows are returned.

There are various ways to construct a query so that it evaluates the date based on only the date component. Here's one example:

WHERE YEAR(datecreated) = YEAR(GETDATE())
  AND MONTH(datecreated) = MONTH(GETDATE())
  AND DAY(datecreated) = DAY(GETDATE())

The unfortunate reality is that any query using a function on the column means that if an index exists on the column, it can't be used.

Best Answer

Related Solutions

SQL Server DateTime – How to Return Only the Date

SQL – How to Get Date from Datetime in SQL Server

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