如何在ActiveRecord准备好的语句中使ruby数组为ax，y，z

Question

I am using Ruby on Rails 3.20 and Postgres 9.4 on heroku and have the following fragement:

metro_area_ids=[3,4,7]
a=metro_area_ids.join(',')
self.where("metro_area_ids ilike '%-?-%' or metro_area_ids ilike '%-?-%' or metro_area_ids='%-?-%'", a)  # how to make this array be 3,4,7 joining doesn't work

I'd like to be able to pass an array of values from 1 to 10 (as an arbitrary upper limit) and be able to query against our table with a postgres ilike statement.

but I get

ActiveRecord::PreparedStatementInvalid: wrong number of bind variables (1 for 2) in: metro_area_ids ilike '%-?-%' or metro_area_ids ilike '%-?-%'

How would I make this work for an arbitrary number of inputs in the array?

edit

so this doesn't work

Queryable.where("metro_area_ids ilike '%-?-%' or metro_area_ids ilike '%-?-%'",[1,13])

so this does work which is what I'm trying to simulate:

Queryable.where("metro_area_ids ilike '%-?-%' or metro_area_ids ilike '%-?-%'",1,13)

Answer 1

This is because you reference many arguments through ? while specifying only one (a string), use named placeholders or specify every element of the array alone.

using named placeholders

metro_area_ids={ st: 3, nd: 4, th: 7 }
self.where("metro_area_ids ilike '%-:st-%' or metro_area_ids ilike '%-:nd-%' or metro_area_ids='%-:th-%'", metro_area_ids) 

provide each element separatly

self.where("metro_area_ids ilike '%-?-%' or metro_area_ids ilike '%-?-%' or metro_area_ids='%-?-%'", metro_area_ids[0], metro_area_ids[1], metro_area_ids[2]) 

Answer 2

you can simply test it by $ ruby test.rb and copy following content to the file

require 'active_record'

class Metro < ActiveRecord::Base
  establish_connection adapter: 'sqlite3', database: 'foobar.db'
  connection.create_table table_name, force: true do |t|
    t.string :metro_area_ids
  end
end

Metro.create!([
  { metro_area_ids: '1,2,3,4' },
  { metro_area_ids: '2,3,4,5' },
  { metro_area_ids: '3,4,5,6' },
])
metros = Metro.where("metro_area_ids LIKE ?", "%2,3%")
p metros.inspect
#=> [#<Metro id: 1, metro_area_ids: \"1,2,3,4\">,
     #<Metro id: 2, metro_area_ids: \"2,3,4,5\">]

Answer 3

像这样：

Queryable.where("metro_area_ids ilike '?' or metro_area_ids ilike '?'", "%-#{1}-%", "%-#{13}-%")