Summary for Window Functions

SQL allows us to read a table using TABLE, select rows with a suitable WHERE clause, or groups of rows based on common criteria with GROUP BY. By those means, we can get only so far, though. In particular, retrieving implicit information like computations on pairs of rows is difficult, if not impossible, depending on the problem statement. Hence, SQL introduced window functions that enable us to perform row-based queries seamlessly.

Frame specification

Row-based queries in SQL consist of a window function and a window specification. Four optional components constitute ...