These are methods for the dplyr select(), rename(), and relocate()
generics. They generate the SELECT clause of the SQL query.
These functions do not support predicate functions, i.e. you can
not use where(is.numeric) to select all numeric variables.
# S3 method for class 'tbl_lazy'
select(.data, ...)
# S3 method for class 'tbl_lazy'
rename(.data, ...)
# S3 method for class 'tbl_lazy'
rename_with(.data, .fn, .cols = everything(), ...)
# S3 method for class 'tbl_lazy'
relocate(.data, ..., .before = NULL, .after = NULL)A lazy data frame backed by a database query.
<data-masking> Variables, or
functions of variables. Use desc() to sort a variable in descending
order.
A function used to transform the selected .cols. Should
return a character vector the same length as the input.
<tidy-select> Columns to rename;
defaults to all columns.
<tidy-select> Destination of
columns selected by .... Supplying neither will move columns to the
left-hand side; specifying both is an error.
library(dplyr, warn.conflicts = FALSE)
db <- memdb_frame(x = 1, y = 2, z = 3)
db %>% select(-y) %>% show_query()
#> <SQL>
#> SELECT `x`, `z`
#> FROM `dbplyr_A18VI8wNwu`
db %>% relocate(z) %>% show_query()
#> <SQL>
#> SELECT `z`, `x`, `y`
#> FROM `dbplyr_A18VI8wNwu`
db %>% rename(first = x, last = z) %>% show_query()
#> <SQL>
#> SELECT `x` AS `first`, `y`, `z` AS `last`
#> FROM `dbplyr_A18VI8wNwu`