How to Join First Row in SQL Server?
When working with SQL Server, we may encounter situations where we need to join to the first row of a related table. This could be to retrieve the earliest record for each group or to extract initial data for further analysis. To solve this problem, we’ll explore three different approaches are as follows:
- Using Subqueries
- Using ROW_NUMBER()
- Using CROSS APPLY
Let’s set up an environment
To understand How to Join to first row in SQL Server we need a table on which we will perform various operations and queries. Here we will consider a table called EmployeeReviews which contains EmployeeID, ReviewDate, Rating, and department as Columns.
-- Create EmployeeReviews table
CREATE TABLE EmployeeReviews (
EmployeeID INT,
ReviewDate DATE,
Rating INT,
PRIMARY KEY (EmployeeID, ReviewDate)
);
-- Insert sample data into the EmployeeReviews table
INSERT INTO EmployeeReviews (EmployeeID, ReviewDate, Rating) VALUES
(1, '2024-01-01', 4),
(1, '2024-02-01', 5),
(2, '2024-01-15', 3),
(3, '2024-02-01', 4),
(3, '2024-03-01', 5),
(4, '2024-01-01', 5),
(4, '2024-02-01', 4);
Output:
How to Join to First Row in SQL Server
Joining the first row in SQL Server can be a common requirement in various scenarios, such as when we need to retrieve specific data associated with the first occurrence of a particular group or when you want to fetch additional details related to the first record in a result set.
In this article, We will learn about How to Join to first row in SQL Server by understanding various approaches along with the examples and so on.