query() fails when FROM clause refers to object in non-global calling environment

[ianmcook]

When the query() function is called inside a function, it fails when the FROM clause refers to a data frame that exists in that function's environment but not in the global environment. For example:

foo <- function(dat, sql) {
    query(sql)
}
foo(iris, "SELECT Species, COUNT(*) FROM dat GROUP BY Species")
# Error: No data frame exists with the name dat