One, the SQL AVG () function

1. SQL AVG () function

The AVG () function returns the average of a numeric column.

The following is the data selected from the "Access_log" table:

+-----+---------+-------+------------+|Aid|site_id|Count|Date|+-----+---------+-------+------------+| 1 | 1 | 45 | 2016-05-10 || 2 | 3 | 100 | 2016-05-13 || 3 | 1 | 230 | 2016-05-14 || 4 | 2 | 10 | 2016-05-14 || 5 | 5 | 205 | 2016-05-14 || 6 | 4 | 13 | 2016-05-15 || 7 | 3 | 220 | 2016-05-15 || 8 | 5 | 545 |2016-05-16  ||  9 |3 |201 |2016-05-17  |+-----+---------+-------+------------+           

SQL AVG () instance

The following SQL statement gets the average value from the "Count" column of the "Access_log" table:

Instance Select AVG (count) As countaverageFrom Access_log;

Execute the above SQL output as follows:

The following SQL statement selects "site_id" and "count" for access above the average number of accesses:

Instance Select site_id, Count from Access_log
WHERE count > (SELECT AVG (count) from Access_log);

Execute the above SQL output as follows:

One, the SQL AVG () function