Make a order_expr node.

order_expr_se(source, expr, env = parent.frame())

Arguments

source

source to select from.

expr

expression to order_expr in ascending order.

env

environment to look for values in.

Value

select columns node.

Examples


if (requireNamespace("DBI", quietly = TRUE) && requireNamespace("RSQLite", quietly = TRUE)) {
  my_db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
  d <- rq_copy_to(my_db, 'd',
                   data.frame(AUC = 0.6, R2 = 0.2))
  optree <- order_expr_se(d, "AUC/R2")
  cat(format(optree))
  sql <- to_sql(optree, my_db)
  cat(sql)
  print(DBI::dbGetQuery(my_db, sql))
  DBI::dbDisconnect(my_db)
}
#> mk_td("d", c(
#>   "AUC",
#>   "R2")) %.>%
#>  order_expr(.,
#>    AUC/R2)
#> SELECT * FROM (
#>  SELECT
#>   `AUC`,
#>   `R2`
#>  FROM
#>   `d`
#> ) tsql_74319839297534752089_0000000000
#> ORDER BY `AUC` / `R2`
#>   AUC  R2
#> 1 0.6 0.2