How do I use functions like CONCAT(), etc. in ARel?
activerecord, arel, ruby
Solution
Use `NamedFunction`:
name = Arel::Attribute.new(Arel::Table.new(:countries), :name)
func = Arel::Nodes::NamedFunction.new 'zomg', [name]
Country.select([name, func]).to_sql
Problem
Is there a way to have `ARel` write (sanitized, possibly aliased, etc.) column names into `CONCAT()` and other SQL functions? Here's how to do it with AVG()... ``` ?> name = Arel::Attribute.new(Arel::Table.new(:countries), :name) => #<struct Arel::Attributes::Attribute [...] ?> population = Arel::Attribute.new(Arel::Table.new(:countries), :population) => #<struct Arel::Attributes::Attribute [...] ?> Country.select([name, population.average]).to_sql => "SELECT `countries`.`name`, AVG(`countries`.`population`) AS avg_id FROM `countries`" ``` (yes, I know that `avg_id` would be the same in every row, just trying to illustrate my question) So what if I wanted a different function? ``` ?> Country.select(xyz).to_sql # Arel::Concat.new(name, population) or something? => "SELECT CONCAT(`countries`.`name`, ' ', `countries`.`population`) AS concat_id FROM `countries`" ``` Thanks!