How to compare datetime with only date in SQL Server
DON'T be tempted to do things like this:
Select * from [User] U where convert(varchar(10),U.DateCreated, 120) = '2014-02-07'
This is a better way:
Select * from [User] U
where U.DateCreated >= '2014-02-07' and U.DateCreated < dateadd(day,1,'2014-02-07')
see: What does the word “SARGable” really mean?
EDIT + There are 2 fundamental reasons for avoiding use of functions on data in the where clause (or in join conditions).
- In most cases using a function on data to filter or join removes the ability of the optimizer to access an index on that field, hence making the query slower (or more "costly")
- The other is, for every row of data involved there is at least one calculation being performed. That could be adding hundreds, thousands or many millions of calculations to the query so that we can compare to a single criteria like
2014-02-07
. It is far more efficient to alter the criteria to suit the data instead.
"Amending the criteria to suit the data" is my way of describing "use SARGABLE
predicates"
And do not use between either.
the best practice with date and time ranges is to avoid BETWEEN and to always use the form:
WHERE col >= '20120101' AND col < '20120201' This form works with all types and all precisions, regardless of whether the time part is applicable.
http://sqlmag.com/t-sql/t-sql-best-practices-part-2 (Itzik Ben-Gan)
If you are on SQL Server 2008 or later you can use the date datatype:
SELECT *
FROM [User] U
WHERE CAST(U.DateCreated as DATE) = '2014-02-07'
It should be noted that if date column is indexed then this will still utilise the index and is SARGable. This is a special case for dates and datetimes.
You can see that SQL Server actually turns this into a > and < clause:
I've just tried this on a large table, with a secondary index on the date column as per @kobik's comments and the index is still used, this is not the case for the examples that use BETWEEN or >= and <:
SELECT *
FROM [User] U
WHERE CAST(U.DateCreated as DATE) = '2016-07-05'
According to your query
Select * from [User] U where U.DateCreated = '2014-02-07'
SQL Server is comparing exact date and time i.e (comparing 2014-02-07 12:30:47.220
with 2014-02-07 00:00:00.000
for equality). that's why result of comparison is false
Therefore, While comparing dates you need to consider time also. You can useSelect * from [User] U where U.DateCreated BETWEEN '2014-02-07' AND '2014-02-08'
.
Of-course this is an old thread but to make it complete.
From SQL 2008 you can use DATE datatype so you can simply do:
SELECT CONVERT(DATE,GETDATE())
OR
Select * from [User] U
where CONVERT(DATE,U.DateCreated) = '2014-02-07'