Return columns used
columns_used(x, ..., using = NULL)
rquery operation tree.
generic additional arguments (not used)
character, if not NULL set of columns used from above.
vector of table qualified column names.
if (requireNamespace("DBI", quietly = TRUE) && requireNamespace("RSQLite", quietly = TRUE)) {
my_db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
d1 <- rq_copy_to(my_db, 'd1',
data.frame(AUC = 0.6, R2 = 0.2))
d2 <- rq_copy_to(my_db, 'd2',
data.frame(AUC = 0.6, D = 0.3))
optree <- natural_join(d1, d2, by = "AUC")
cat(format(optree))
print(columns_used(optree))
DBI::dbDisconnect(my_db)
}
#> mk_td("d1", c(
#> "AUC",
#> "R2")) %.>%
#> natural_join(.,
#> mk_td("d2", c(
#> "AUC",
#> "D")),
#> jointype = "INNER", by = c('AUC'))
#> $d1
#> [1] "AUC" "R2"
#>
#> $d2
#> [1] "AUC" "D"
#>