ActiveRecord :: StatementInvalid（PG :: UndefinedFunction

Question

I have a checkbox field (car_options) that stores an array of values for a number of selections.

I need to query all Car records that contain any of the values in another array.

["a","b","c","d","e","f"] that contains any of the following ["b", "z","v"]

Schema

t.string "car_options", default: [], array: true

Check if attr array contains any of element from given array in Rails

My query:

 Car.where('car_options && ARRAY[?]', ["4door","3seat"])

Error

ActiveRecord::StatementInvalid (PG::UndefinedFunction: ERROR: operator does not exist: character varying[] && text[]) LINE 1: ...cars".* FROM "cars" WHERE (car_options && ARRAY['...^

HINT: No operator matches the given name and argument types. You might need to add explicit type casts. : SELECT "cars".* FROM "cars" WHERE (car_options && ARRAY['BY']) LIMIT $1

Answer 1

PostgreSQL is complaining because ARRAY[?] ends up being a text[] (ie an array of text ) where as your car_options column is character varying[] (ie array of character varying ).

You could cast the array literal:

Car.where('car_options && ARRAY[?]::varchar[]', ["4door","3seat"])

or make the column text[] :

t.text "car_options", default: [], array: true

I'd probably go with the latter because PostgreSQL handles text and character varying types the same internally, the only time you'd bother with varchar (AKA character varying or t.string in a migration) is if you have a hard limit on how long they should be (and even then you could use text with a CHECK constraint).