我们可以实现这一点，如果是，那么SQL查询将是什么

Question

我有一个表有以下类型的数据：

+---------+------+--------+
| market  | type | amount |
+---------+------+--------+
| LTCBTC  | SELL |   0.15 |
| XMRBTC  | BUY  |  0.005 |
| DASHBTC | BUY  |  0.002 |
| ADABTC  | BUY  |      7 |
| IOTABTC | BUY  |      1 |
| LTCBTC  | BUY  |   0.17 |
| XRPBTC  | BUY  |     12 |
| ETHBTC  | BUY  |   0.03 |
| BCCBTC  | BUY  |  0.005 |
| ETHBTC  | SELL |  0.124 |
| LTCBTC  | BUY  |   0.02 |
| XMRBTC  | BUY  |  0.004 |
| DASHBTC | BUY  |  0.002 |
| ADABTC  | BUY  |      6 |
| IOTABTC | BUY  |      1 |
| XRPBTC  | BUY  |     10 |
| BCCBTC  | BUY  |  0.004 |
| ETHBTC  | BUY  |  0.025 |
| XMRBTC  | BUY  |  0.006 |
| DASHBTC | BUY  |  0.002 |
| LTCBTC  | BUY  |   0.02 |
| ETHBTC  | SELL |  0.026 |
| ETHBTC  | SELL |  0.004 |
| BCCBTC  | SELL |  0.005 |
| XRPBTC  | SELL |     14 |
+---------+------+--------+

这是我直到今天买或卖的硬币对的信息。我想找到我为每对配对的确切数量的硬币。

所以基本上我想要以下回复：

+---------+------+----------------------+
| market  | type | sum(amount)          |
+---------+------+----------------------+
| ADABTC  | BUY  |                   13 |
| BCCBTC  | BUY  |        0.00400000019 |
| DASHBTC | BUY  | 0.006000000284984708 |
| ETHBTC  | BUY  |         -0.098999999 |
| IOTABTC | BUY  |                    2 |
| LTCBTC  | BUY  |         0.0599999949 |
| XMRBTC  | BUY  |  0.01500000013038516 |
| XRPBTC  | BUY  |                    8 |
+---------+------+----------------------+

有人可以帮我查询相同的问题吗？

谢谢

Answer 1

我想简单的CASE和GROUP BY应该有效

select market,
       sum(case when type = 'sell' then -amount
                when type = 'buy' then amount end)
from data
group by market