Aggregate Expressions
An aggregate expression applies an aggregate function across the rows or groups of rows selected by a query.
An aggregate expression only can appear in the select list or HAVING
clause of a SELECT
statement. It is invalid in other clauses such as WHERE
, because those clauses are evaluated before the results of aggregates are formed.
Syntax
An aggregate expression has the following format:
aggregate‑function ( [ * ] [ ALL | DISTINCT ] expression )
Parameters
aggregate‑function | A Vertica function that aggregates data over groups of rows from a query result set. |
ALL | DISTINCT
|
Specifies which input rows to process:
|
expression | A value expression that does not itself contain an aggregate expression. |