column_references: Return the column references in a parsed SQL query
Description
Returns a character vector containing all the column references
in the clauses of a parsed SQL SELECT statement
Usage
column_references(tree, from = TRUE)
Value
A character vector containing all the unique column references found
in the SELECT, FROM (if from = TRUE), WHERE,
GROUP BY, HAVING, and ORDER BY clauses of the
SELECT statement
Arguments
tree
a list returned by parse_query containing named
elements representing the clauses of a SQL SELECT statement
from
a logical value indicating whether to include the column
references from the join conditions in the FROM clause
Details
The returned character vector includes only column
references, not table references. Column aliases assigned in the
SELECT list are not included unless they are used in other clauses.
my_query <- "SELECT f.flight,
manufacturer, p.model
FROM flights f
JOIN planes p USING (tailnum);"column_references(parse_query(my_query), from = FALSE)