columns_used: Return columns used

In rquery: Relational Query Generator for Data Manipulation at Scale

Return columns used

Description

Return columns used

Usage

columns_used(x, ..., using = NULL)

Arguments

x	rquery operation tree.
...	generic additional arguments (not used)
using	character, if not NULL set of columns used from above.

Value

vector of table qualified column names.

Examples

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)
}

rquery documentation built on Aug. 20, 2023, 9:06 a.m.