Aggregate Functions (General) , Window Functions (General)
Returns some value of the expression from the group. The result is non-deterministic.
ANY_VALUE( [ DISTINCT ] <expr1> )
ANY_VALUE( [ DISTINCT ] <expr1> ) OVER ( [ PARTITION BY <expr2> ] )
The DISTINCT keyword can be specified for this function, but it does not have any effect.
When used as a window function:
This function does not support:
ORDER BY sub-clause in the OVER() clause.
Using ANY_VALUE with GROUP BY Statements¶
ANY_VALUE can simplify and optimize the performance of GROUP BY statements. A common problem for many queries is that the result of a query with a GROUP BY clause can only contain expressions used in the GROUP BY clause itself, or results of aggregate functions. For example:
SELECT customer.id , customer.name , SUM(orders.value) FROM customer JOIN orders ON customer.id = orders.customer_id GROUP BY customer.id , customer.name;
In this query, the
customer.name attribute needs to be in the GROUP BY to be included in the result. This is unnecessary (e.g. when
customer.id is known to be unique) and makes the computation
possibly more complex and slower. Another option is to use an aggregate function. For example:
SELECT customer.id , MIN(customer.name) , SUM(orders.value) FROM customer JOIN orders ON customer.id = orders.customer_id GROUP BY customer.id;
This simplifies the GROUP BY clause, but still requires computing the MIN function, which incurs an extra cost.
With ANY_VALUE, you can execute the following query:
SELECT customer.id , ANY_VALUE(customer.name) , SUM(orders.value) FROM customer JOIN orders ON customer.id = orders.customer_id GROUP BY customer.id;