When I started learning SQL, the window functions (analytic functions) were the most difficult to understand. Although you do not need to use the window function when using a database simply as a place to store and retrieve data, it is a v…

For example, "In a user's event log, I want to extract the last event the user performed." Sometimes you want to retrieve the last record of data divided by groups. The window function can be used to obtain the following WITH tbl AS ( SELE…