如何在iReport中使用SQL查询同一项目的多个SUM

sum（当-condition-然后计数else 0结束的情况）

SELECt  SUM(case when $P{oneDayAgo} <= datetime then count else 0 end) as 'today',  SUM(case when $P{oneWeekAgo} <= datetime then count else 0 end) as 'thisweek',  SUM(count) as 'thismonth'FROM  statisticsWHERe   name = "test"  AND $P{oneMonthAgo} <= datetime  AND datetime <= $P{now}

请注意，如果需要平均值，请确保将NULL替换为0。