EXPLAIN EXTENDED

In the previous articles I wrote about emulating some of the analytic functions in MySQL.

Today, I'll write about four more userful functions: FIRST_VALUE, LAST_VALUE, LEAD and LAG.

These functions also do not have aggregate analogs.

FIRST VALUE(column) returns the value of column from the first row of the grouping set.

LAST_VALUE(column) returns the value of column from the last row of the grouping set.

This can be illustrated by the following query:
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