SQL
OVER, PARTITION BY and Window ORDER BY
Window functions compute across related rows without collapsing them. Learn the OVER clause, PARTITION BY, window ORDER BY, and how they differ from G...
Window Functions
OVER, PARTITION BY, ranking, offset functions and frames.
4 notes
Notes
SQL
ROW_NUMBER, RANK, DENSE_RANK and NTILE
The four ranking functions, how each handles ties, and the top N per group pattern that makes ROW_NUMBER the most used window function in SQL.
SQL
LAG, LEAD, FIRST_VALUE and LAST_VALUE
Reading other rows from the current row: the previous value, the next value, and the first or last in the window - with the LAST_VALUE frame trap.
SQL
Frames, Running Totals and Moving Averages
The frame clause decides which rows each calculation sees. Learn ROWS versus RANGE, running totals, moving averages, and when a window beats GROUP BY.