An aggregating expression is an expression where any field name is contained in exactly one of the aggregating functions. For example, you could use the aggregating function
max in the statement
group max(A) as Agg by B.
GROUP BY and
WINDOW statements must include an aggregating expression.
GROUP BY or
WINDOW statement, the aggregating expression does not have to include a field name. For example:
GROUP 1.0 as price BY product_id;
is a valid statement that does not have a field name in the aggregating expression.
A few additional examples of statements with aggregating expressions:
GROUP first(price) + 1.0 as first_price BY product_id;
GROUP array(max(us_price), max(eu_price)) as prices BY product_id;
WINDOW max(price_1) + max(price_2) as max_price BY product_id;
WINDOW array(max(price_1), max(price_2)) as prices BY product_id;
are all valid aggregations.
Note: Nested aggregating functions are not allowed. A sequence of aggregations must be provided instead. For example, these statements:
GROUP first(1.0 + max(price)) as max_price BY product_id;
WINDOW mean((price - mean(price)) * (price - mean(price))) as var_price BY product_id
are not allowed.
Updated 6 months ago