Distinct

Mostly used with Select:#

User.select(:name).distinct
SELECT DISTINCT "users"."name" FROM "users"

If nothing is passed, id is used:#

[6] pry(main)> User.all.distinct.count
(2.3ms) SELECT COUNT(DISTINCT "users"."id") FROM "users"
=> 165

While using with Pluck, it uses the items in the pluck to make it distinct.#

  • Single
User.distinct.pluck(:name).count
(0.9ms) SELECT DISTINCT "users"."name" FROM "users"
=> 165
  • Multiple
User.distinct.pluck(:name, :shortname).count
(0.9ms) SELECT DISTINCT "users"."name", "users"."shortname" FROM "users"
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