How to Simulate Lag and Lead Window Functions in MS Access Have you ever wondered how you could calculate something in your query field that used the value in the row previous to the current row? Like when something changes status and you want to know how long it was in the previous status? This is where Lag and Lead window functions come in, and these are regularly used in larger RDBMS systems like SQL Server or Oracle. While MS Access does not have native Lag and Lead functions, we can simulate two of the most commonly used ones (Lag and Lead by one record) by using several methods. One method is simple and easy to deploy for small numbers of rows. Another method is much better for when you want to calculate Lag and Lead on large tables. Related Videos: How to Use a Pass Through Query in MS Access - SQL Server Example https://www.youtube.com/watch?v=JCeEBb3mR7E How to Simulate Lag and Lead Window Functions You are watching this video now! How to Filter by Month in MS Access Queries, Forms, and Reports https://www.youtube.com/watch?v=c45ny4vQGFs How to Use Reference Expressions to Get Form Values in MS Access https://www.youtube.com/watch?v=I2JU95lnz_w How to Create String Aggregates in Microsoft Access https://www.youtube.com/watch?v=ItCS-g1K2zk Follow us on social media: https://www.facebook.com/mackenziedataanalytics https://twitter.com/seamacke https://www.instagram.com/seamacke/ https://www.linkedin.com/in/psmackenzie/ Get Microsoft Office including Access: https://click.linksynergy.com/fs-bin/click?id=BdGJecFFM8A&offerid=1160033.10004289&type=3&subid=0 Got a YouTube Channel? I use TubeBuddy, it is awesome. Give it a try: https://www.tubebuddy.com/seanmackenziedataengineering https://www.reddit.com/user/seamacke Need MS Access Database Support? Contact me today! http://www.mackenziemackenzie.com/ Check out some of my earlier videos on MS Access: “How to Format Dates in MS Access Queries, Forms, and VBA Code” : https://www.youtube.com/watch?v=TaohJxP0-MI "VBA Mod Function with DoEvents: Prevent Not Responding Messages and Provide Feedback on Access Forms " https://www.youtube.com/watch?v=BPT-_H1ir6k "Iif, If Then Else, and Select Case in MS Access" https://www.youtube.com/watch?v=E5HbVmxHxSQ "How to Query the Last Row in a Series in Microsoft Access" https://www.youtube.com/watch?v=5cnwHyn4dnI "How to Make Cascading Combo Boxes in MS Access" https://www.youtube.com/watch?v=at0uaGSnUco "How to Open a RecordSet in Access VBA and Loop Through the Records" https://www.youtube.com/watch?v=7HckYjH_wg4 ms access lag, ms access lead, lag window function ms access, lead window function ms access, ms access dmax function, dmax function, ms access subquery, vba recordset loop, vba recordset update, ms access query performance, vba dao recordset, vba currentdb, ms access previous record