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public interface OrderedAggregateFunction<T>
An ordered aggregate function.
An ordered aggregate function is an aggregate function with a mandatory
Oracle-specific WITHIN GROUP (ORDER BY ..)
clause. An example is
LISTAGG
:
The above function groups books by author and aggregates titles
into a concatenated string.
SELECT LISTAGG(TITLE, ', ')
WITHIN GROUP (ORDER BY TITLE)
FROM T_BOOK
GROUP BY AUTHOR_ID
Ordered aggregate functions can be further converted into window functions
using the OVER(PARTITION BY ..)
clause. For example:
SELECT LISTAGG(TITLE, ', ')
WITHIN GROUP (ORDER BY TITLE)
OVER (PARTITION BY AUTHOR_ID)
FROM T_BOOK
Method Summary | |
---|---|
AggregateFunction<T> |
withinGroupOrderBy(Collection<SortField<?>> fields)
Add an WITHIN GROUP (ORDER BY ..) |
AggregateFunction<T> |
withinGroupOrderBy(Field<?>... fields)
Add an WITHIN GROUP (ORDER BY ..) |
AggregateFunction<T> |
withinGroupOrderBy(SortField<?>... fields)
Add an WITHIN GROUP (ORDER BY ..) |
Method Detail |
---|
AggregateFunction<T> withinGroupOrderBy(Field<?>... fields)
WITHIN GROUP (ORDER BY ..)
clause to the ordered
aggregate function
AggregateFunction<T> withinGroupOrderBy(SortField<?>... fields)
WITHIN GROUP (ORDER BY ..)
clause to the ordered
aggregate function
AggregateFunction<T> withinGroupOrderBy(Collection<SortField<?>> fields)
WITHIN GROUP (ORDER BY ..)
clause to the ordered
aggregate function
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