How to Correctly Query for Dates Greater Than a Specified Date in SQL Server?

Date Comparison in SQL Server: Querying for Dates Greater than Specified

In SQL Server, queries often involve comparing dates to filter and retrieve specific data. When attempting to query for dates greater than a particular date, it's essential to handle date formats correctly.

Consider the following query:

SELECT *
FROM dbo.March2010 A
WHERE A.Date >= 2010-04-01;

where A.Date is represented in the format '2010-03-04 00:00:00.000'. However, this query may not return the expected results.

The reason for this issue lies in the interpretation of the expression 2010-04-01. In SQL Server, mathematical calculations are performed on date values when they are not enclosed in single quotes. Subtracting 4 and 1 from 2010 yields 2005, which is not the intended comparison value.

To resolve this issue, the expression must be explicitly converted to a datetime data type using the Convert function. The corrected query is:

select *
from dbo.March2010 A
where A.Date >= Convert(datetime, '2010-04-01' )

Now, the query will correctly compare the dates and return records where the A.Date value is greater than or equal to '2010-04-01'.

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