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package org.jooq;

import org.jetbrains.annotations.*;


// ...
import static org.jooq.SQLDialect.H2;
import static org.jooq.SQLDialect.POSTGRES;

An ordered-set aggregate function.

An ordered-set aggregate function is an aggregate function with a mandatory
Oracle-specific WITHIN GROUP (ORDER BY ..) clause. An example is
LISTAGG: 
SELECT   LISTAGG(TITLE, ', ')
         WITHIN GROUP (ORDER BY TITLE)
FROM     T_BOOK
GROUP BY AUTHOR_ID
 The above function groups books by author and aggregates titles
into a concatenated string.

Ordered-set 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

Author:
Lukas Eder/**
 * An ordered-set aggregate function.
 * <p>
 * An ordered-set aggregate function is an aggregate function with a mandatory
 * Oracle-specific <code>WITHIN GROUP (ORDER BY ..)</code> clause. An example is
 * <code>LISTAGG</code>: <code><pre>
 * SELECT   LISTAGG(TITLE, ', ')
 *          WITHIN GROUP (ORDER BY TITLE)
 * FROM     T_BOOK
 * GROUP BY AUTHOR_ID
 * </pre></code> The above function groups books by author and aggregates titles
 * into a concatenated string.
 * <p>
 * Ordered-set aggregate functions can be further converted into window functions
 * using the <code>OVER(PARTITION BY ..)</code> clause. For example: <code><pre>
 * SELECT LISTAGG(TITLE, ', ')
 *        WITHIN GROUP (ORDER BY TITLE)
 *        OVER (PARTITION BY AUTHOR_ID)
 * FROM   T_BOOK
 * </pre></code>
 *
 * @author Lukas Eder
 */
public interface OrderedAggregateFunctionOfDeferredType {

    
Add an WITHIN GROUP (ORDER BY ..) clause to the ordered
aggregate function
/**
     * Add an <code>WITHIN GROUP (ORDER BY ..)</code> clause to the ordered
     * aggregate function
     */
    @NotNull
    @Support({ H2, POSTGRES })
    <T> AggregateFilterStep<T> withinGroupOrderBy(OrderField<T> field);
}