Aggregates over a discrete field

Uses very generic dplyr code to aggregate data. Because of this approach, the calculations automatically run inside the database if `data` has a database or sparklyr connection. The `class()` of such tables in R are: tbl_sql, tbl_dbi, tbl_sql

db_compute_count(data, x, ..., y = n())

Arguments

data	A table (tbl)
x	A discrete variable
...	A set of named or unamed aggregations
y	The aggregation formula. Defaults to count (n)

Examples

# Returns the row count per am
mtcars %>%
  db_compute_count(am)
#> # A tibble: 2 x 2
#>      am `n()`
#>   <dbl> <int>
#> 1     0    19
#> 2     1    13

# Returns the average mpg per am
mtcars %>%
  db_compute_count(am, mean(mpg))
#> # A tibble: 2 x 2
#>      am `mean(mpg)`
#>   <dbl>       <dbl>
#> 1     0        17.1
#> 2     1        24.4

# Returns the average and sum of mpg per am
mtcars %>%
  db_compute_count(am, mean(mpg), sum(mpg))
#> # A tibble: 2 x 3
#>      am `mean(mpg)` `sum(mpg)`
#>   <dbl>       <dbl>      <dbl>
#> 1     0        17.1       326.
#> 2     1        24.4       317.