如何在休眠查询语言中按日期分组而没有时间戳？

Question

我想从按日期分组的表中获取数据，但是由于我的日期列数据类型为datetime。

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

由于datePerformed与时间戳，它的组包括时间戳，所以我已经使用了上面的查询

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

我遇到这样的异常，

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

我希望此查询将我的数据集与没有时间戳的数据分组，我该怎么办？

Answer 1

尝试：

group by datePerformed::date

或更好

group by cast(datePerformed as date)

Answer 2

这是我使用date_trunc和Hibernate sqlGroupProjection所有可能的postgres时间范围的完整解决方案。

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

我遇到了同样的问题，这种方式对我有用：

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

我也尝试过这种方法，但是不起作用：

group by l.launchTime::date

要么

group by cast(l.launchTime as date)