How to read the contents of an .sql file into an R script to run a query?

I've had trouble with reading sql files myself, and have found that often times the syntax gets broken if there are any single line comments in the sql. Since in R you store the sql statement as a single line string, if there are any double dashes in the sql it will essentially comment out any code after the double dash.

This is a function that I typically use whenever I am reading in a .sql file to be used in R.

getSQL <- function(filepath){
  con = file(filepath, "r")
  sql.string <- ""

  while (TRUE){
    line <- readLines(con, n = 1)

    if ( length(line) == 0 ){
      break
    }

    line <- gsub("\\t", " ", line)

    if(grepl("--",line) == TRUE){
      line <- paste(sub("--","/*",line),"*/")
    }

    sql.string <- paste(sql.string, line)
  }

  close(con)
  return(sql.string)
}

I've found for queries with multiple lines, the read_file() function from the readr package works well. The only thing you have to be mindful of is to avoid single quotes (double quotes are fine). You can even add comments this way.

Example query, saved as query.sql

SELECT 
COUNT(1) as "my_count"
-- comment goes here
FROM -- tabs work too
  my_table

I can then store the results in a data frame with

df <- dbGetQuery(con, statement = read_file('query.sql'))