In SQL query design, how would you typically apply a date range filter to return rows whose OrderDate falls between a given start date and end date inclusive?

Introduction / Context:
Filtering rows by date ranges is a very common requirement in reporting and application queries. Examples include retrieving orders placed between two dates or showing transactions for a specific period. Structured Query Language provides straightforward syntax for specifying inclusive ranges on date columns. This question asks how to apply a date range filter so that only rows whose OrderDate lies between a specified start date and end date are returned.

Given Data / Assumptions:

• There is a table with a date or datetime column named OrderDate.
• The application provides parameters or variables such as StartDate and EndDate.
• The goal is to include all rows where OrderDate is greater than or equal to StartDate and less than or equal to EndDate.
• We want an efficient, server side filter rather than manual filtering in the client.

Concept / Approach:
In Structured Query Language, the WHERE clause specifies conditions that rows must satisfy to be included in the result set. To filter by a date range, you can use comparisons such as OrderDate >= StartDate and OrderDate <= EndDate. Many dialects also support the BETWEEN operator, which is syntactic sugar for an inclusive range comparison. The expression OrderDate BETWEEN StartDate AND EndDate is equivalent to the combined greater than or equal to and less than or equal to checks. Using this condition in the WHERE clause ensures that filtering occurs on the database server and that only matching rows are returned to the client.

Step-by-Step Solution:
Step 1: Identify the column that holds the date to filter on, for example OrderDate. Step 2: Determine the start and end date parameters, such as @StartDate and @EndDate, provided by the application or user input. Step 3: Construct a WHERE clause that restricts OrderDate to values between these two parameters. Step 4: Use the BETWEEN operator for clarity: WHERE OrderDate BETWEEN @StartDate AND @EndDate. Step 5: Check the options and see that option a correctly demonstrates this pattern.

Verification / Alternative check:
For example, suppose @StartDate is 2024-01-01 and @EndDate is 2024-01-31. A query such as SELECT * FROM Orders WHERE OrderDate BETWEEN @StartDate AND @EndDate returns all orders in January 2024. The equivalent form SELECT * FROM Orders WHERE OrderDate >= @StartDate AND OrderDate <= @EndDate yields the same result. This confirms that the BETWEEN syntax in option a matches typical practice for date range filtering.

Why Other Options Are Wrong:
Option b suggests checking only the year, which would include dates from the entire year, not just the desired range, and would ignore the month and day components. Option c proposes retrieving all rows and then filtering manually in the user interface, which is inefficient and does not satisfy the requirement to apply the filter within the query. Option d uses GROUP BY without any comparison operators, which groups rows but does not apply a filtering condition based on a range of dates.

Common Pitfalls:
A frequent pitfall is mishandling time components when the column is datetime rather than pure date. For example, using OrderDate <= EndDate may miss rows that occur later in the day if EndDate is stored as a date without time. In such cases, developers sometimes adjust the end date to the next day and use OrderDate < next day. However, for conceptual exam questions, using BETWEEN with clearly defined dates is usually sufficient. Always be careful with time zones and inclusivity in real applications.

Final Answer:
You typically apply a date range filter by using a WHERE clause with BETWEEN, for example: WHERE OrderDate BETWEEN @StartDate AND @EndDate, as shown in option a.