Question

我想从单个查询中的表格中选择最近200,100和50行收盘价的 SUM 。下面给出的是200行的查询。

SELECT SUM(Close_price) as tot200 FROM cash_data ORDER BY date_added LIMIT 0,200

任何人都可以帮助我。

Answer 1

您可以使用子查询 -

SELECT 
(SELECT SUM(Close_price) FROM cash_data ORDER BY date_added LIMIT 0,200) as tot200, 
(SELECT SUM(Close_price) FROM cash_data ORDER BY date_added LIMIT 0,100)  as tot100,
(SELECT SUM(Close_price) FROM cash_data ORDER BY date_added LIMIT 0,50)  as tot50

Answer 2

要在没有任何子选择的单个选择中进行制作，您可以使用排名变量和有条件的总和

SELECT @rank := @rank + 1, 
       SUM(case when @rank <= 50 then Close_price else 0 end) as top_50_sum, 
       SUM(case when @rank <= 100 then Close_price else 0 end) as top_100_sum,
       SUM(case when @rank <= 200 then Close_price else 0 end) as top_200_sum
FROM cash_data 
cross join (select @rank := 0) r
ORDER BY date_added 
LIMIT 0,200

Answer 3

感谢所有回复。实际上两个答案都有效，但我选择了第二个，并根据我的需要做了一些改变。以下是最终查询

SELECT 
(SELECT SUM(Close_price)/200 FROM (SELECT Close_price FROM cash_data WHERE SERIES='$series' AND SYMBOL='$symbol' AND date_added <= '$date' ORDER BY date_added DESC LIMIT 0,200) as tot200) as avg200, 
(SELECT SUM(Close_price)/100 FROM (SELECT Close_price FROM cash_data WHERE SERIES='$series' AND SYMBOL='$symbol' AND date_added <= '$date' ORDER BY date_added DESC LIMIT 0,100) as tot100) as avg100,
(SELECT SUM(Close_price)/50 FROM (SELECT Close_price FROM cash_data WHERE SERIES='$series' AND SYMBOL='$symbol' AND date_added <= '$date' ORDER BY date_added DESC LIMIT 0,50) as tot50) as avg50

谢谢大家。

如何在mysql查询中添加多个限制？

3 个答案: