SQL查询以明智地获取净利润股票

Question

tid	stock	sid	sval	type
1	abc	1	100	buy
2	abc	2	120	buy
3	xyz	3	300	buy
4	abc	4	240	sell
5	xyz	5	250	sell

查询得到以下输出

输出

stock	profit/loss
abc	20
xyz	-50

另一个不同的查询得到以下输出

输出 2

stock	profit/loss
abc	9.09%
xyz	-16.6%

解释- 对于股票 abc：总投资 = 220，利润 = 20，百分比 = (20/220)*100 = 9.09%

对于股票 xyz：总投资 = 300，利润 = -50，百分比 = (-50/300)*100 = -16.6%

Answer 1

您可以使用case 表达式将“卖出”计为利润，将“买入”计为损失，然后将它们相加：

SELECT   stock, SUM(CASE type WHEN 'sell' THEN sval
                              WHEN 'buy'  THEN sval * -1
                    END) as "profit/loss"
FROM     stocks
GROUP BY stock