How Can I Correctly Query Dates in SQL Server to Avoid Unexpected Results?

Using Dates in SQL Server Queries

In SQL Server, it is crucial to consider data types when querying dates. Your query, which attempted to find all dates greater than or equal to 2010-04-01, was unsuccessful because you used 2010-4-01 as a mathematical expression, essentially treating it as 2005.

To properly query for dates, you need to convert the date to the datetime data type and use single quotes. Here's the corrected query:

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

By converting the string '2010-04-01' to a datetime value, SQL Server can accurately compare it to the datetime data type in your table.

Alternatively, you could use the following syntax, which implicitly converts the string to datetime:

select *
from dbo.March2010 A
where A.Date >= '2010-04-01'

However, it's generally recommended to use the explicit CONVERT function for clarity and maintainability.

Remember, when querying dates in SQL Server, always ensure that you consider the data types and use the appropriate conversion functions to avoid unexpected results.

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