Active Record - Where IN with multiple columns - ruby-on-rails

Question

I have a query that needs to fetch from a table that meet two columns requirements exactly. So if I have users table with columns, age and score.
SELECT * FROM users where (age, score) IN ((5,6), (9,12), (22,44)..)
In my web app I am getting this pairs from an ajax request, and the number could be quite big. How do I construct an Active Record query for this?.
I am working on postgres database

Answer 1

Ideally, we will build a query string based on the input. Eg
ages_and_scores = [ [5, 6], [9, 12], [22, 44] ]
query_string = ages_and_scores.map do |pair|
"(age = #{pair[0]} AND score = #{pair[1]})"
end.join(" OR ")
# => (age = 5 AND score = 6) OR (age = 9 AND score = 12) OR (age = 22 AND score = 44)
Finally, your query will be
User.where(query_string)
You may correct the logic of how to build the query string since ages_and_scores is in a different format to my example.
Improvement
ages_and_scores = [ [5, 6], [9, 12], [22, 44] ]
query_params = []
query_template = ages_and_scores.map{ |_| "(age = ? AND score = ?)" }.join(" OR ")
# => (age = ? AND score = ?) OR (age = ? AND score = ?) OR (age = ? AND score = ?)
User.where(query_template, *ages_and_scores.flatten)

Answer 2

Another method, to reconstruct the exact query used by the OP based on a multicolumn IN clause.
A more compact form of SQL, with arguable better semantics:
ages_and_scores = [ [5, 6], [9, 12], [22, 44] ]
query_string = ages_and_scores.map { |pair| "(#{pair[0]},#{pair[1]})" }.join(",")
User.where("(age, score) IN (#{query_string})")

Answer 3

In rails 5, you can use OR, so you can do:
ages_and_scores = [ [5, 6], [9, 12], [22, 44] ]
ages_and_scores.map do |age, score|
User.where(age: age).where(score: score)
end.reduce(&:or)
# => should produce something like:
# SELECT * FROM users WHERE (`users`.`age` = 5 AND `users`.`score` = 6 OR `users`.`age` = 9 AND `users`.`score` = 12 OR `users`.`age` = 22 AND `users`.`score` = 44)
I believe this is sql-injection free and pure ActiveRecord.

Answer 4

Hey you can try this way in mysql:
ages_and_scores = [ [5, 6], [9, 12], [22, 44] ]
User.where("CONCAT(age,',', score) in (?)",ages_and_scores.map{|b| "#{b[0]},#{b[1]}"})
In PG database you can directly Concat using:
(age || ' ,' || score)

Answer 5

Another solution would be to use Arel, which would help keep things DB agnostic.
ages_and_scores = [ [5, 6], [9, 12], [22, 44] ]
first_age, first_score = ages_and_scores.shift
t = User.arel_table
users = ages_and_scores.inject(User.where(t[:age].eq(first_age)).where(t[:score].eq(first_score))) { |query, age_score| query.or(User.where(t[:age].eq(age_score[0])).where(t[:score].eq(age_score[1]))) }
Essentially how this works:
Separate the first value pair from the array
Get the arel table so that you can build the query
Use the inject method from Ruby's Enumerable module to iterate through the rest of the array adding in all of the or conditions ... but starting with the initial two values in the first where query.
Finally, you will have an Arel query which returns all of the users matching your criteria ... and it should work across any DB supported by Rails (Arel).

Answer 6

Base on Yuki Inoue 's comment. I have modified a little bit and it's working smoothly
ages_and_scores = [ [5, 6], [9, 12], [22, 44] ]
ages_and_scores.each do |age, score|
User.where(age: age).map(score: score)
end.reduce(&:or)
# => should produce something like:
# SELECT * FROM users WHERE (`users`.`age` = 5 AND `users`.`score` = 6 OR `users`.`age` = 9 AND `users`.`score` = 12 OR `users`.`age` = 22 AND `users`.`score` = 44)