Question

贸易——数据表1

代表行动价格

1 P-4, 3 P-3, 4 FS

2 SELL, 325

3 出售45 75

3支

表1

姓名

1 RCC

2 REG

SELECT SUM( IF( trade_data.action =   BUY , price, 0 ) ) AS   BUYSUM ,
       SUM( IF( trade_data.action =   SELL , price, 0 ) ) AS   BUYSELL , 
       AVG( trade_data.percent ) AS peravg, symbol. * 
FROM  `trade_data` 
INNER JOIN  `symbol` ON trade_data.symbol = symbol.id

This Query Gives me One Row But there Are Two Row are available at this Condition. But When I change the query As

SELECT trade_data.* , symbol. * 
FROM  `trade_data` 
INNER JOIN  `symbol` ON trade_data.symbol = symbol.id

Then this Query Gives me Exact 2 Rows.

Answer 1

Use group by with aggregate function ex.

SELECT SUM( IF( trade_data.action =   BUY , price, 0 ) ) AS   BUYSUM , SUM( IF( trade_data.action =   SELL , price, 0 ) ) AS   BUYSELL , AVG( trade_data.percent ) AS peravg, symbol. *

FROM trade_data INNER JOIN symbol ON trade_data.symbol = symbol.id group by symbol.id

Answer 2

www.un.org/Depts/DGACM/index_french.htm 因此,在这里,SUM(价格)将给你价格总额,增加每行的价格价值。而总价值总是单一数值,因此,你们只能获得单一增长产出。

这种希望有助于。

Answer 3

您正在使用<代码>AVG()和SUM(功能,这就是为什么你们正在获得单一重整。

The AVG() Function
The AVG() function returns the average value of a numeric column.


The SUM() Function
The SUM() function returns the total sum of a numeric column.

如果您有多个<条码>贸易_数据.symbol = 符号.id。 (超过1例) 按分类,以获得每份记录的总和和平均数,并注明出处,因为只有1份<代码>,>symbol.id和trade_data.symbol。你们只有一份记录。

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