sql - 在postgresql中显示表的唯一属性和总值

Question

我有一个表，其中包含 stamp_type 和 amount 列，如下所示

                          stamp_type                          | amount
--------------------------------------------------------------+--------
 GENERAL STAMP                                                |  11000
 GENERAL STAMP                                                |  25000
 COURT FEE STAMP                                              |   9800
 SPECIAL ADHESIVE                                             | 721000
 GENERAL STAMP                                                | 125000
 COURT FEE STAMP                                              |  21000

现在我要显示如下:

    stamp_type                                                    | amount
    GENERAL STAMP                                                   161000
    COURT FEE STAMP                                                 30800
    SPECIAL ADHESIVE                                                721000

TOTAL:912800

我无法显示唯一值。任何人都可以给我建议查询。我尝试使用 Distinct 但效果不佳。

Answer 1

select * from 
(
select  0 as srt, stamp_type, sum(amount) as SumAmount from t group by stamp_type
union 
select 1 as srt, 'Total' as stamp_type, sum(amount) as SumAmount from t 
) b order by srt