Windowing functions are a critical tool for grouping rows of data
that are related to other rows. But they go far beyond the
regular aggregate functions found in MySQL 5.7 and earlier. In
MySQL 8 you do not have to collapse all the information down into
a single output row. Each row can retain its individual identity
but the server can analyze the data as a unit.
Statistics and Damned Lies Finding the total Population of
the District Texas from the world.city table
is simple.
SQL> select District, sum(Population)
from city where district = 'Texas';
+----------+-----------------+
| District | sum(Population) |
+----------+-----------------+
| Texas
| 9208281 |
+----------+-----------------+
1 row in set (0.0068 sec)
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Showing entries 1 to 1
Jul
29
2018
Showing entries 1 to 1