从具有公共属性的单独行添加属性

Question

我试图将具有公共属性的表中两行的两个整数相加。这是表格：

=> select * from hello;
            exname            | location  | numitems
------------------------------+-----------+----------
 Notes                        | Gallery B |       10
 Notes to Coins               | Gallery C |       16
 Silver Dollars               | Gallery A |        9
 Silver Dollars               | Gallery D |        2
(4 rows)

我试图查询表格以创建一个结果，该结果包含两行exname =＆＃39; Silver Dollars＆＃39;与numitems结合起来，总结了这两行。

我正在尝试创建具有此结果的查询：

            exname            | numitems
------------------------------+----------
 Notes                        |       10
 Notes to Coins               |       16
 Silver Dollars               |       11
(3 rows)

请注意，9和2总计为11.我该怎么做？

Answer 1

这样可行。

select exname, sum(numitems) numitems 
from hello
group by exname ;

Answer 2

尝试这个

select exname, sum(numitems)as numitems 
from hello
group by exname