我试图用买入的美元减去卖出的美元。
**|Tran_ID|Currency_type|currency_Amount|Local_Amount| Rate |Tran_type| **
| 85 | USD | 2500 | 1581.54 |1.58074 | Bought |
| 78 | USD | 3487.57 | 2206.29 |1.58074 | Bought |
| 86 | USD | 100 | 63.26 |1.58074 | Bought |
| 87 | USD | 94.17 | 63.26 |1.48866 | Sold |
| 88 | USD | 2600 | 1746.54 |1.48866 | Sold |
| 89 | USD | 2600 | 1746.54 |1.48866 | Sold |
我可以使用下面的查询添加出售或购买的美元总值
SELECT Currency_type, sum( currency_Amount ) AS total_bought
FROM Transaction
WHERE Currency_type= 'USD'
AND Tran_type = 'Bought' <== **or 'Sold'**
结果如下
**|Currency_type | total_bought |**
|USD |6087.570068359375|