Источник данных Oracle, возвращая пустое соединение

Использование dplyr и tidyr:

library(dplyr)
library(tidyr)

data %>%
  group_by(group) %>%
  summarize(value1_min = min(value1),
        value1_max = max(value1),
        value2_min = min(value2),
        value2_max = max(value2),
        value3_n = length(unique(value3)),
        value3_perc1 = length(sum(value3==1))/length(unique(value3)),
        value3_perc2 = length(sum(value3==2))/length(unique(value3)),
        value3_perc3 = length(sum(value3==3))/length(unique(value3))
        ) %>%
  gather(review, value, -group) %>%
  spread(group, value)

Результат:

# A tibble: 7 x 3
  review         `0`    `1`
  <chr>        <dbl>  <dbl>
1 value1_max   9.00  10.0  
2 value1_min   1.00   2.00 
3 value2_max   9.00  10.0  
4 value2_min   1.00   2.00 
5 value3_n     3.00   3.00 
6 value3_perc1 0.333  0.333
7 value3_perc2 0.333  0.333
8 value3_perc3 0.333  0.333