Plansplaining part 28 – The curious case of the missing FIRST_VALUE function
1 Comment
In part twenty-eight of the plansplaining series, I’ll wrap up the six-part mini-series on window functions. After covering the basics, fast-track optimization, window frames ending at UNBOUNDED FOLLOWING, window frames specified with RANGE instead of ROWS, and LAG and LEAD, we will look at the LAST_VALUE and FIRST_VALUE analytical functions, and find that a function we would have expected to be available as an internal aggregate function does not exist at all! We’ll also find out how SQL Server works around that. LAST_VALUE We already encountered the LAST_VALUE internal aggregate function in the previous post, where it is used to…
