/*
 * Copyright 2016-2018 shardingsphere.io.
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * </p>
 */

package io.shardingsphere.core.executor.sql.execute.result;

import io.shardingsphere.core.merger.QueryResult;

import java.io.InputStream;
import java.sql.SQLException;
import java.util.Calendar;
import java.util.Collection;
import java.util.Map;
import java.util.Map.Entry;

/**
 * Distinct query result.
 *
 * @author panjuan
 */
public final class DistinctQueryResult implements QueryResult {

    private final Collection<QueryResult> queryResults;

    private final Map<Integer, Collection<Object>> columnIndexAndDistinctValusesMap;

    public DistinctQueryResult(final Collection<QueryResult> queryResults) {
        queryResults
    }

    @Override
    public boolean next() {
        if (resultData.hasNext()) {
            currentRow = resultData.next();
            return true;
        }
        currentRow = null;
        return false;
    }

    @Override
    public Object getValue(final int columnIndex, final Class<?> type) {
        return currentRow.get(columnIndex - 1);
    }

    @Override
    public Object getValue(final String columnLabel, final Class<?> type) {
        return currentRow.get(getIndexByColumnLabel(columnLabel));
    }

    @Override
    public Object getCalendarValue(final int columnIndex, final Class<?> type, final Calendar calendar) {
        return currentRow.get(columnIndex - 1);
    }

    @Override
    public Object getCalendarValue(final String columnLabel, final Class<?> type, final Calendar calendar) {
        return currentRow.get(getIndexByColumnLabel(columnLabel));
    }

    @Override
    public InputStream getInputStream(final int columnIndex, final String type) {
        return (InputStream) currentRow.get(columnIndex - 1);
    }

    @Override
    public InputStream getInputStream(final String columnLabel, final String type) {
        return (InputStream) currentRow.get(getIndexByColumnLabel(columnLabel));
    }

    @Override
    public boolean wasNull() {
        return null == currentRow;
    }

    @Override
    public int getColumnCount() {
        return columnLabelAndIndexMap.size();
    }

    @Override
    public String getColumnLabel(final int columnIndex) throws SQLException {
        for (Entry<String, Integer> entry : columnLabelAndIndexMap.entries()) {
            if (columnIndex == entry.getValue()) {
                return entry.getKey();
            }
        }
        throw new SQLException("Column index out of range", "9999");
    }
}

@@ -719,24 +719,52 @@
 QueryResult;
+%0Aimport lombok.SneakyThrows;
 %0A%0Aimport jav
@@ -863,24 +863,50 @@
 Collection;%0A
+import java.util.HashMap;%0A
 import java.
@@ -942,16 +942,38 @@
 p.Entry;
+%0Aimport java.util.Set;
 %0A%0A/**%0A *
@@ -1175,26 +1175,19 @@
 nteger, 
-Collection
+Set
 %3CObject%3E
@@ -1308,16 +1308,21 @@
         
+this.
 queryRes
@@ -1325,16 +1325,320 @@
 yResults
+ = queryResults;%0A        %0A    %7D%0A    %0A    @SneakyThrows%0A    private Map%3CInteger, Collection%3CObject%3E%3E getColumnIndexAndDistinctValusesMap(final Collection%3CQueryResult%3E queryResults) %7B%0A        Map%3CInteger, Collection%3CObject%3E%3E result = new HashMap%3C%3E(queryResults.iterator().next().getColumnCount());%0A        
 %0A    %7D%0A%0A

use Map<Integer, Set<Object>>