Question

The following SQL I am trying to run is returning sql_string of “SELECT id FROM people WHERE id IN (“16”)“:

@ids = ["1", "6"]

sql_string = <<-SQL
  SELECT id
  FROM people
  WHERE id IN ("#{@ids}")
SQL

Can someone please help modify the above query so it will create the sql_string of “SELECT id FROM people WHERE id IN (1, 6)“

Answer 1

Just throwing @ids in the query will concatenate the array and give you "16". You’ll want to run @ids.join(',') to comma separate them. Plus you need to wrap the expression part of the string in #{}. Otherwise it will treat it as literal.

@ids = ["1", "6"]

sql_string = <<-SQL
  SELECT id
  FROM people
  WHERE id IN (#{@ids.join(',')})
SQL

P.S. There are very few valid reasons for manually writing a whole SQL query in Rails. You should look into using ActiveRecord to do something like People.find_all_by_id(@ids) instead.