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package org.jooq;

import org.jooq.impl.DSL;

An expression to be used exclusively in GROUP BY clauses.

The SELECT .. GROUP BY clause accepts a variety of expressions, mostly ordinary Field expressions, but also some special expressions usable only in the GROUP BY clause, such as DSL.groupingSets(Field<?>[][]). 

Example:

// Assuming import static org.jooq.impl.DSL.*;
using(configuration)
   .select(ACTOR.LAST_NAME)
   .from(ACTOR)
   .groupBy(ACTOR.LAST_NAME) // GroupField reference here
   .fetch();

 Instances can be created using DSL.groupingSets(Field<?>[][]) and related methods, or by creating a subtype. 
Author:
Lukas Eder/**
 * An expression to be used exclusively in <code>GROUP BY</code> clauses.
 * <p>
 * The <code>SELECT .. GROUP BY</code> clause accepts a variety of expressions,
 * mostly ordinary {@link Field} expressions, but also some special expressions
 * usable only in the <code>GROUP BY</code> clause, such as
 * {@link DSL#groupingSets(Field[][])}.
 * <p>
 * <strong>Example:</strong>
 * <p>
 * <code><pre>
 * // Assuming import static org.jooq.impl.DSL.*;
 *
 * using(configuration)
 *    .select(ACTOR.LAST_NAME)
 *    .from(ACTOR)
 *    .groupBy(ACTOR.LAST_NAME) // GroupField reference here
 *    .fetch();
 * </pre></code>
 * <p>
 * Instances can be created using {@link DSL#groupingSets(Field[][])} and
 * related methods, or by creating a subtype.
 *
 * @author Lukas Eder
 */
public interface GroupField extends QueryPart {

}