Getting the date for “yesterday” in SQL may seem like a simple task, but it can become a bit challenging depending upon the specifics of your project requirements. However, if you have a firm grasp of SQL and its functions, you can efficiently provide the solution. SQL or Structured Query Language is a domain-specific language used in programming and designed for managing data held in a relational database management system.
We need a robust technique to calculate a date corresponding to “yesterday,” applicable across all server scenarios. Let’s explore the best solution:
SELECT DATEADD(day, -1, GETDATE()) as YesterdayDate
Understanding the Code
We use a SQL Server inbuilt function, ‘DATEADD,’ combined with ‘GETDATE.’ The DATEADD function subtracts one day (-1) from the current date, delivered by GETDATE.
DATEADD is a powerful function introduced in SQL Server to perform operations with date and time values. It helps us to add or subtract date parts, including day, month, year, hour, minute, and more from a date or time value.
GETDATE is another inbuilt function used in SQL Server to fetch the current timestamp in the server’s respective time zone.
Step-by-Step Code Explanation
- Firstly, the GETDATE() function obtains the current date and time as per your SQL Server goes.
- Next, the DATEADD() function comes into play. DATEADD() accepts three parameters, the first indicates the part of the date to add or subtract, the second parameter implies the increment or decrement value, and the third parameter represents the date.
From this code snippet, DATEADD subtracts `-1` (1 day) from the date retrieved by GETDATE() function, effectively giving us “yesterday’s” date.
SQL Server Functions and Libraries
In this problem, we didn’t use any external libraries–SQL Server provides all the required functions. Understanding the application of these functions for different scenarios is vital for a SQL developer. Ensure you are understanding correctly when and how to use DATEADD, GETDATE and other built-in SQL Server functions.
Apart from `DATEADD` and `GETDATE`, SQL Server supports a vast list of date and time functions like `DATEDIFF`, `DAY`, `MONTH`, `YEAR`, `SYSDATETIME`, `CURRENT_TIMESTAMP`, etc. Extensive knowledge about these functions and their applications can assist you in solving more complex problems.
Hope this article helps your understanding of the SQL server’s inbuilt functions, specifically ‘DATEADD’ and ‘GETDATE’.
