I found this in the guide, but have no idea how to implement the same
yii\db\Query::count(): returns the result of a COUNT query. Other
similar methods include sum($q), average($q), max($q), min($q), which
support the so-called aggregational data query. $q parameter is mandatory
for these methods and can be either the column name or expression.
Say for example I have a table name ‘billing’ with columns:
Total - 620.00
How I implement using