Sql 总和栏总计和两个不同期间总计

我知道这听起来有点奇怪，但我有两个问题要问

sum（）列总计-NetAmount

有两个时期的数据进行比较-基本金额之和

我的问题如下

select a.usage_id BillingGroup, a.usage_desc BGDesc, sum(a.base_amount) NetAmount
from cdi_item_dtl a, cdi_invoice_hdr b
where a.tran_type = 'RM_CMI'
and a.tran_no = b.tran_no
and b.tran_date between '2014-06-01 00:00:00.000' and '2014-06-30 00:00:00.000'
group by a.usage_id, a.usage_desc
order by a.usage_id

这给了我NetAmount所有组的总数，我想得到NetAmount的总数

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第二点，正如该查询显示的2014年6月期间，是否有可能将NetAmount2013作为2013年6月的下一列，并在单个查询中列出？

快速简便的方法如下：您可能应该避免硬编码字符串，并与

月份（）和
年份（）进行一些比较，以改进这一点
函数，但这将向您展示基本思想

select 
    a.usage_id BillingGroup, 
    a.usage_desc BGDesc, 
    sum(CASE WHEN b.tran_date between '2014-06-01 00:00:00.000' and '2014-06-30 00:00:00.000' THEN a.base_amount ELSE 0 END) NetAmount2014,
    sum(CASE WHEN b.tran_date between '2013-06-01 00:00:00.000' and '2013-06-30 00:00:00.000' THEN a.base_amount ELSE 0 END) NetAmount2013
from cdi_item_dtl a, cdi_invoice_hdr b
where 
    a.tran_type = 'RM_CMI'
    and a.tran_no = b.tran_no
    and 
      (
        b.tran_date between '2014-06-01 00:00:00.000' and '2014-06-30 00:00:00.000'
        OR b.tran_date between '2013-06-01 00:00:00.000' and '2013-06-30 00:00:00.000'
      )
group by a.usage_id, a.usage_desc
order by a.usage_id