如何在休眠查詢語言中按日期分組而沒有時間戳？

Question

我想從按日期分組的表中獲取數據，但是由於我的日期列數據類型為datetime。

"select to_char(datePerformed, 'yyyy-mm-dd'), sum(sendAmount) from AppTransaction group by to_char(datePerformed, 'yyyy-mm-dd')"

由於datePerformed與時間戳，它的組包括時間戳，所以我已經使用了上面的查詢

group by to_char(datePerformed, 'yyyy-mm-dd')"

我遇到這樣的異常，

java.lang.IllegalArgumentException: Cannot format given Object as a Date

我希望此查詢將我的數據集與沒有時間戳的數據分組，我該怎么辦？

Answer 1

嘗試：

group by datePerformed::date

或更好

group by cast(datePerformed as date)

Answer 2

這是我使用date_trunc和Hibernate sqlGroupProjection所有可能的postgres時間范圍的完整解決方案。

public enum PostgresDateTrunc {

    second,
    minute,
    hour,
    day,
    week,
    month,
    quarter,
    year;

    public String getPostgresGroupExpression(String dtField, String alias) {
        return String.format("date_trunc('%s', %s) as %s", name(), dtField, alias);
    }

}

public class GenericRepository {

    public List calculateTimeGroupingStats(PostgresDateTrunc trunc, String timeGroupField, String...calculatedFields) {
        Criteria criteria = createCriteria();
        // adjust criteria object here

        ProjectionList projection = Projections.projectionList().
            add(Projections.alias(Projections.sqlGroupProjection(
                trunc.getPostgresGroupExpression(timeGroupField, "timeGroupField"),
                "timeGroupField", new String[]{"timeGroupField"}, new Type[]{StandardBasicTypes.DATE}),
                "timeGroupField")).
            add(Projections.alias(Projections.rowCount(), "count"));

        for (String calculatedField : calculatedFields) {
            projection.
                add(Projections.alias(Projections.sum(calculatedField), calculatedField + "Sum")).
                add(Projections.alias(Projections.avg(calculatedField), calculatedField + "Avg"));
        }

        criteria.addOrder(Order.asc("timeGroupField"));

        criteria.setProjection(projection);

        return criteria.list();
    }

}

Answer 3

我遇到了同樣的問題，這種方式對我有用：

SELECT to_char(l.launchTime, 'mm-dd-yyyy'), count(l) 
  FROM Launch l 
 GROUP BY to_char(l.launchTime, 'mm-dd-yyyy')

我也嘗試過這種方法，但是不起作用：

group by l.launchTime::date

要么

group by cast(l.launchTime as date)