根据type,operation,k_symbol对amount分组求和以及求平均,amount列存在空值(不知道是不是这个原因导致结果显示全部为0),代码如下
```result_1_1=sqldf("select type,operation,k_symbol,
- count(*) as count_id,
- sum(amount) as sum_of_amount,
- avg(amount) as avg_of_amount from trans group by type,operation,k_symbol")
![图片说明](https://img-ask.csdn.net/upload/201905/14/1557823867_723229.jpg)
考虑会不会是空值的原因,于是修改代码,将空值赋值为0,代码如下:
result_1_1<-sqldf("select type,operation,k_symbol,
- count(*) as count_id,
- sum(ifnull(amount,0)) as sum_of_amount,
- avg(ifnull(amount,0)) as avg_of_amount from trans group by type,operation,k_symbol") ``` 但是结果和上图一样,希望大神能帮忙解答一下,感激不尽