Name
DB.DBA.VECTOR_OR_NULL_AGG — Returns a vector of passed values.
Synopsis
vector DB.DBA.VECTOR_OR_NULL_AGG ( |
value_expression any
); |
Description
DB.DBA.VECTOR_OR_NULL_AGG returns
a vector of passed values. Similar to DB.DBA.VECTOR_AGG() but returns NULL instead
of an empty vector if no arguments were actually passed.
The order of items in the vector repeats the order of passing individual values to the aggregate.
Parameters
value_expression
Value of item for aggregation.
Return Types
Any. If no arguments were actually passed returns NULL instead of an empty vector.
Examples
Example24.3.Simple Use
As the order of items in the vector repeats the order of passing individual values to the aggregate, it is possible to write, for instance:
-- Get an ordered vector of X-es SELECT DB.DBA.VECTOR_OR_NULL_AGG (subquery.X) FROM (SELECT X FROM ... ORDER BY X) as subquery
or
SELECT DB.DBA.VECTOR_OR_NULL_AGG (subquery.Y) FROM (SELECT Y FROM ... ORDER BY X) as subquery
and get vector of Y-s that are ordered by matching values of X-es.