pkgload::load_all()
#> ℹ Loading duckplyr

df <- tibble(g = c(1, 1, 2, 2, 2), x = 1:5)

duckplyr_summarise(df, out = sum(x))
#> materializing:
#> ---------------------
#> --- Relation Tree ---
#> ---------------------
#> Aggregate [sum(x)]
#>   r_dataframe_scan(0x107915988)
#> 
#> ---------------------
#> -- Result Columns  --
#> ---------------------
#> - out (HUGEINT)
#> 
#> # A tibble: 1 × 1
#>     out
#>   <dbl>
#> 1    15
summarise(df, out = sum(x))
#> # A tibble: 1 × 1
#>     out
#>   <int>
#> 1    15

duckplyr_summarise(df, .by = g, out = 1)
#> materializing:
#> ---------------------
#> --- Relation Tree ---
#> ---------------------
#> Aggregate [g, 1.0]
#>   r_dataframe_scan(0x126678ec8)
#> 
#> ---------------------
#> -- Result Columns  --
#> ---------------------
#> - g (DOUBLE)
#> - out (DOUBLE)
#> 
#> # A tibble: 2 × 2
#>       g   out
#>   <dbl> <dbl>
#> 1     1     1
#> 2     2     1
summarise(df, .by = g, out = 1)
#> # A tibble: 2 × 2
#>       g   out
#>   <dbl> <dbl>
#> 1     1     1
#> 2     2     1

duckplyr_summarise(df, out = 1)
#> materializing:
#> ---------------------
#> --- Relation Tree ---
#> ---------------------
#> Aggregate [1.0]
#>   r_dataframe_scan(0x107aebb08)
#> 
#> ---------------------
#> -- Result Columns  --
#> ---------------------
#> - out (DOUBLE)
#> 
#> # A tibble: 5 × 1
#>     out
#>   <dbl>
#> 1     1
#> 2     1
#> 3     1
#> 4     1
#> 5     1
summarise(df, out = 1)
#> # A tibble: 1 × 1
#>     out
#>   <dbl>
#> 1     1