How to Query the Latest Version of Each Row in SQL

Querying the Latest Version of Each Row

Write a SQL query to retrieve the latest version of each row in a temporal table.

Solution:

-- Retrieve the latest version of each row.
SELECT EmployeeID, Name, Position, SysStartTime, SysEndTime
FROM Employees
FOR SYSTEM_TIME ALL
WHERE SysEndTime = '9999-12-31 23:59:59.9999999';

Explanation:

• Purpose of the Query :
• The goal is to demonstrate how to query the latest version of each row in a temporal table.
• Key Components :
• FOR SYSTEM_TIME ALL: Retrieves all versions of rows.
• SysEndTime = '9999-12-31 23:59:59.9999999': Filters for rows currently valid.
• Why Query Latest Versions? :
• Querying the latest version ensures access to the most up-to-date data.
• It simplifies reporting and analysis.
• Real-World Application :
• In payroll systems, querying latest versions ensures accurate salary calculations.

Additional Notes:

• Use this query for operational reporting or real-time analytics.
• Combine with filters to focus on specific subsets of data.
• Important Considerations:
• Ensure that the query targets the correct table.

For more Practice: Solve these Related Problems:

• Write a SQL query to retrieve the latest version of each row in a temporal table named "Products".
• Write a SQL query to fetch the most recent state of all rows in a temporal table named "Orders".
• Write a SQL query to display the current version of rows in a temporal table named "Customers".
• Write a SQL query to extract the latest version of rows in a temporal table named "Inventory".

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Previous SQL Exercise: Dropping a Column from a Temporal Table.
Next SQL Exercise: Migrating Data from a Non-Temporal Table to a Temporal Table.