SQL Server DAY Function
By: Daniel Calbimonte
The DAY function returns the day part of the date as an integer from the date or datetime provided.
- Date – Is the date or datetime provided.
Simple DAY Example
The following example will show the day for March 9, 2021.
SELECT DAY('3-9-2021 5:00:55 PM') as day
DAY function with NULL values
If the parameter of the DAY function is NULL, a NULL value will be returned.
SELECT DAY(NULL) as day
Conversion Failed Error for DAY Function
A typical error will occur if the date is invalid. The following example is using a wrong day number (32).
SELECT DAY('3-32-2021 5:00:55 PM') as day
The error message displayed is:
Conversion failed when converting date and/or time from character string.
Using DAY Function with just Time
If the DAY function receives just a time value, the value returned is 1.
SELECT DAY('5:00:55 PM') as day
DAY Function with Data from a Table
The following example will show the day for the StartDate.
SELECT StartDate, DAY(StartDate) as day FROM [Production].[ProductCostHistory]
- Mimic timestamp behavior of other database platforms to store last modified date
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