Effortlessly Add Days to Dates in SQL Server 2005 with `DATEADD`

The DATEADD function manipulates dates and times in SQL Server. It takes three arguments:

1. datepart: This specifies what part of the date you want to modify (e.g., day, month, year).
2. number: This is the integer value representing the number of units (e.g., 1 for day, 2 for months) to add or subtract (negative values subtract).
3. date: This is the date value you want to modify.

Here's how to add one day to a date called existing_date:

SELECT DATEADD(day, 1, existing_date) AS new_date;

This code:

1. Uses DATEADD with the day argument for the date part.
2. Specifies 1 for adding one day.
3. Uses the existing_date as the date to modify.
4. Assigns the result to the alias new_date.

Example:

DECLARE @existing_date DATE = '2024-02-26';

SELECT DATEADD(day, 1, @existing_date) AS new_date;

This code declares a variable @existing_date with the value "2024-02-26" and then adds one day using DATEADD. The result, stored in new_date, will be "2024-02-27".

• Incorrect data type: Ensure both number and existing_date have compatible data types. If existing_date is a string, convert it to DATE before using DATEADD.

Example (converting string to date):

SELECT DATEADD(day, 1, CAST('2024-02-26' AS DATE)) AS new_date;

• Adding multiple days: Change the number argument in DATEADD to reflect the desired number of days to add (e.g., 3 for three days).

Remember, DATEADD modifies the original date only within the query. If you want to permanently change the date in a table, use appropriate UPDATE statements.