VALID_UNSCOPING_VALUES =[:where, :select, :group, :order, :lock, :limit, :offset, :joins, :left_outer_joins, :annotate, :includes, :from, :readonly, :having, :optimizer_hints])

Instance Public methods


Returns a new relation, which is the logical intersection of this relation and the one passed as an argument.

The two relations must be structurally compatible: they must be scoping the same model, and they must differ only by where (if no group has been defined) or having (if a group is present).

Post.where(id: [1, 2]).and(Post.where(id: [2, 3]))
# SELECT `posts`.* FROM `posts` WHERE `posts`.`id` IN (1, 2) AND `posts`.`id` IN (2, 3)
# File activerecord/lib/active_record/relation/query_methods.rb, line 845
def and(other)
  if other.is_a?(Relation)
    raise ArgumentError, "You have passed #{} object to #and. Pass an ActiveRecord::Relation object instead."


Adds an SQL comment to queries generated from this relation. For example:

User.annotate("selecting user names").select(:name)
# SELECT "users"."name" FROM "users" /* selecting user names */

User.annotate("selecting", "user", "names").select(:name)
# SELECT "users"."name" FROM "users" /* selecting */ /* user */ /* names */

The SQL block comment delimiters, “/*” and “*/”, will be added automatically.

# File activerecord/lib/active_record/relation/query_methods.rb, line 1219
def annotate(*args)
  check_if_method_has_arguments!(__callee__, args)


Sets attributes to be used when creating new records from a relation object.

users = User.where(name: 'Oscar') # => 'Oscar'

users = users.create_with(name: 'DHH') # => 'DHH'

You can pass nil to create_with to reset attributes:

users = users.create_with(nil) # => 'Oscar'
# File activerecord/lib/active_record/relation/query_methods.rb, line 1038
def create_with(value)

distinct(value = true)

Specifies whether the records should be unique or not. For example:
# Might return two records with the same name
# Returns 1 record per distinct name
# You can also remove the uniqueness
# File activerecord/lib/active_record/relation/query_methods.rb, line 1102
def distinct(value = true)


Forces eager loading by performing a LEFT OUTER JOIN on args:

# SELECT "users"."id" AS t0_r0, "users"."name" AS t0_r1, ...
# FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" =
# "users"."id"
# File activerecord/lib/active_record/relation/query_methods.rb, line 207
def eager_load(*args)
  check_if_method_has_arguments!(__callee__, args)


Excludes the specified record (or collection of records) from the resulting relation. For example:

# SELECT "posts".* FROM "posts" WHERE "posts"."id" != 1

Post.excluding(post_one, post_two)
# SELECT "posts".* FROM "posts" WHERE "posts"."id" NOT IN (1, 2)

This can also be called on associations. As with the above example, either a single record of collection thereof may be specified:

post = Post.find(1)
comment = Comment.find(2)
# SELECT "comments".* FROM "comments" WHERE "comments"."post_id" = 1 AND "comments"."id" != 2

This is short-hand for .where.not(id: and .where.not(id: [,]).

An ArgumentError will be raised if either no records are specified, or if any of the records in the collection (if a collection is passed in) are not instances of the same model that the relation is scoping.

Also aliased as: without
# File activerecord/lib/active_record/relation/query_methods.rb, line 1261
def excluding(*records)

  unless records.all?(klass)
    raise ArgumentError, "You must only pass a single or collection of #{} objects to ##{__callee__}."


extending(*modules, &block)

Used to extend a scope with additional methods, either through a module or through a block provided.

The object returned is a relation, which can be further extended.

Using a module

module Pagination
  def page(number)
    # pagination code goes here

scope = Model.all.extending(Pagination)[:page])

You can also pass a list of modules:

scope = Model.all.extending(Pagination, SomethingElse)

Using a block

scope = Model.all.extending do
  def page(number)
    # pagination code goes here

You can also use a block and a module list:

scope = Model.all.extending(Pagination) do
  def per_page(number)
    # pagination code goes here
# File activerecord/lib/active_record/relation/query_methods.rb, line 1148
def extending(*modules, &block)
  if modules.any? || block
    spawn.extending!(*modules, &block)


Extracts a named association from the relation. The named association is first preloaded, then the individual association records are collected from the relation. Like so:

# => Returns collection of User records

This is short-hand for:

# File activerecord/lib/active_record/relation/query_methods.rb, line 240
def extract_associated(association)

from(value, subquery_name = nil)

Specifies the table from which the records will be fetched. For example:'title').from('posts')
# SELECT title FROM posts

Can accept other relation objects. For example:'title').from(Topic.approved)
# SELECT title FROM (SELECT * FROM topics WHERE approved = 't') subquery

Passing a second argument (string or symbol), creates the alias for the SQL from clause. Otherwise the alias “subquery” is used:'a.title').from(Topic.approved, :a)
# SELECT a.title FROM (SELECT * FROM topics WHERE approved = 't') a

It does not add multiple arguments to the SQL from clause. The last from chained is the one used:'title').from(Topic.approved).from(Topic.inactive)
# SELECT title FROM (SELECT topics.* FROM topics WHERE = 'f') subquery

For multiple arguments for the SQL from clause, you can pass a string with the exact elements in the SQL from list:

color = "red"
  .from("colors c, JSONB_ARRAY_ELEMENTS(colored_things) AS colorvalues(colorvalue)")
  .where("colorvalue->>'color' = ?", color)
# SELECT c.*
# FROM colors c, JSONB_ARRAY_ELEMENTS(colored_things) AS colorvalues(colorvalue)
# WHERE (colorvalue->>'color' = 'red')
# File activerecord/lib/active_record/relation/query_methods.rb, line 1083
def from(value, subquery_name = nil)
  spawn.from!(value, subquery_name)


Allows to specify a group attribute:
# SELECT "users".* FROM "users" GROUP BY name

Returns an array with distinct records based on the group attribute:[:id, :name])
# => [#<User id: 1, name: "Oscar">, #<User id: 2, name: "Oscar">, #<User id: 3, name: "Foo">]
# => [#<User id: 3, name: "Foo", ...>, #<User id: 2, name: "Oscar", ...>]'name AS grouped_name, age')
# => [#<User id: 3, name: "Foo", age: 21, ...>, #<User id: 2, name: "Oscar", age: 21, ...>, #<User id: 5, name: "Foo", age: 23, ...>]

Passing in an array of attributes to group by is also supported.[:id, :first_name]).group(:id, :first_name).first(3)
# => [#<User id: 1, first_name: "Bill">, #<User id: 2, first_name: "Earl">, #<User id: 3, first_name: "Beto">]
# File activerecord/lib/active_record/relation/query_methods.rb, line 363
def group(*args)
  check_if_method_has_arguments!(__callee__, args)!(*args)

having(opts, *rest)

Allows to specify a HAVING clause. Note that you can't use HAVING without also specifying a GROUP clause.

Order.having('SUM(price) > 30').group('user_id')
# File activerecord/lib/active_record/relation/query_methods.rb, line 903
def having(opts, *rest)
  opts.blank? ? self : spawn.having!(opts, *rest)

in_order_of(column, values)

Allows to specify an order by a specific set of values. Depending on your adapter this will either use a CASE statement or a built-in function.

User.in_order_of(:id, [1, 5, 3])
# SELECT "users".* FROM "users"
#   ORDER BY FIELD("users"."id", 1, 5, 3)
#   WHERE "users"."id" IN (1, 5, 3)
# File activerecord/lib/active_record/relation/query_methods.rb, line 447
def in_order_of(column, values)
  klass.disallow_raw_sql!([column], permit: connection.column_name_with_order_matcher)
  return spawn.none! if values.empty?

  references = column_references([column])
  self.references_values |= references unless references.empty?

  values = { |value| type_caster.type_cast_for_database(column, value) }
  arel_column = column.is_a?(Symbol) ? order_column(column.to_s) : column

    .order!(connection.field_ordered_value(arel_column, values))


Specify relationships to be included in the result set. For example:

users = User.includes(:address)
users.each do |user|

allows you to access the address attribute of the User model without firing an additional query. This will often result in a performance improvement over a simple join.

You can also specify multiple relationships, like this:

users = User.includes(:address, :friends)

Loading nested relationships is possible using a Hash:

users = User.includes(:address, friends: [:address, :followers])


If you want to add string conditions to your included models, you'll have to explicitly reference them. For example:

User.includes(:posts).where(' = ?', 'example')

Will throw an error, but this will work:

User.includes(:posts).where(' = ?', 'example').references(:posts)

Note that includes works with association names while references needs the actual table name.

If you pass the conditions via hash, you don't need to call references explicitly, as where references the tables for you. For example, this will work correctly:

User.includes(:posts).where(posts: { name: 'example' })
# File activerecord/lib/active_record/relation/query_methods.rb, line 191
def includes(*args)
  check_if_method_has_arguments!(__callee__, args)


Allows you to invert an entire where clause instead of manually applying conditions.

class User
  scope :active, -> { where(accepted: true, locked: false) }

User.where(accepted: true)
# WHERE `accepted` = 1

User.where(accepted: true).invert_where
# WHERE `accepted` != 1
# WHERE `accepted` = 1 AND `locked` = 0
# WHERE NOT (`accepted` = 1 AND `locked` = 0)

Be careful because this inverts all conditions before invert_where call.

class User
  scope :active, -> { where(accepted: true, locked: false) }
  scope :inactive, -> { active.invert_where } # Do not attempt it

# It also inverts `where(role: 'admin')` unexpectedly.
User.where(role: 'admin').inactive
# WHERE NOT (`role` = 'admin' AND `accepted` = 1 AND `locked` = 0)
# File activerecord/lib/active_record/relation/query_methods.rb, line 811
def invert_where


Performs JOINs on args. The given symbol(s) should match the name of the association(s).

# SELECT "users".*
# FROM "users"
# INNER JOIN "posts" ON "posts"."user_id" = "users"."id"

Multiple joins:

User.joins(:posts, :account)
# SELECT "users".*
# FROM "users"
# INNER JOIN "posts" ON "posts"."user_id" = "users"."id"
# INNER JOIN "accounts" ON "accounts"."id" = "users"."account_id"

Nested joins:

User.joins(posts: [:comments])
# SELECT "users".*
# FROM "users"
# INNER JOIN "posts" ON "posts"."user_id" = "users"."id"
# INNER JOIN "comments" ON "comments"."post_id" = "posts"."id"

You can use strings in order to customize your joins:

User.joins("LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id =")
# SELECT "users".* FROM "users" LEFT JOIN bookmarks ON bookmarks.bookmarkable_type = 'Post' AND bookmarks.user_id =
# File activerecord/lib/active_record/relation/query_methods.rb, line 586
def joins(*args)
  check_if_method_has_arguments!(__callee__, args)


Alias for: left_outer_joins


Performs LEFT OUTER JOINs on args:

=> SELECT "users".* FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" = "users"."id"
Also aliased as: left_joins
# File activerecord/lib/active_record/relation/query_methods.rb, line 601
def left_outer_joins(*args)
  check_if_method_has_arguments!(__callee__, args)


Specifies a limit for the number of records to retrieve.

User.limit(10) # generated SQL has 'LIMIT 10'

User.limit(10).limit(20) # generated SQL has 'LIMIT 20'
# File activerecord/lib/active_record/relation/query_methods.rb, line 917
def limit(value)

lock(locks = true)

Specifies locking settings (default to true). For more information on locking, please see ActiveRecord::Locking.

# File activerecord/lib/active_record/relation/query_methods.rb, line 944
def lock(locks = true)


Returns a chainable relation with zero records.

The returned relation implements the Null Object pattern. It is an object with defined null behavior and always returns an empty array of records without querying the database.

Any subsequent condition chained to the returned relation will continue generating an empty relation and will not fire any query to the database.

Used in cases where a method or scope could return zero records but the result needs to be chainable.

For example:

@posts = current_user.visible_posts.where(name: params[:name])
# the visible_posts method is expected to return a chainable Relation

def visible_posts
  case role
  when 'Country Manager'
    Post.where(country: country)
  when 'Reviewer'
  when 'Bad User'
    Post.none # It can't be chained if [] is returned.
# File activerecord/lib/active_record/relation/query_methods.rb, line 987
def none


Specifies the number of rows to skip before returning rows.

User.offset(10) # generated SQL has "OFFSET 10"

Should be used with order.

User.offset(10).order("name ASC")
# File activerecord/lib/active_record/relation/query_methods.rb, line 933
def offset(value)


Specify optimizer hints to be used in the SELECT statement.

Example (for MySQL):

Topic.optimizer_hints("MAX_EXECUTION_TIME(50000)", "NO_INDEX_MERGE(topics)")
# SELECT /*+ MAX_EXECUTION_TIME(50000) NO_INDEX_MERGE(topics) */ `topics`.* FROM `topics`

Example (for PostgreSQL with pg_hint_plan):

Topic.optimizer_hints("SeqScan(topics)", "Parallel(topics 8)")
# SELECT /*+ SeqScan(topics) Parallel(topics 8) */ "topics".* FROM "topics"
# File activerecord/lib/active_record/relation/query_methods.rb, line 1177
def optimizer_hints(*args)
  check_if_method_has_arguments!(__callee__, args)


Returns a new relation, which is the logical union of this relation and the one passed as an argument.

The two relations must be structurally compatible: they must be scoping the same model, and they must differ only by where (if no group has been defined) or having (if a group is present).

Post.where("id = 1").or(Post.where("author_id = 3"))
# SELECT `posts`.* FROM `posts` WHERE ((id = 1) OR (author_id = 3))
# File activerecord/lib/active_record/relation/query_methods.rb, line 877
def or(other)
  if other.is_a?(Relation)
    raise ArgumentError, "You have passed #{} object to #or. Pass an ActiveRecord::Relation object instead."


Applies an ORDER BY clause to a query.

order accepts arguments in one of several formats.


The symbol represents the name of the column you want to order the results by.

# SELECT "users".* FROM "users" ORDER BY "users"."name" ASC

By default, the order is ascending. If you want descending order, you can map the column name symbol to :desc.

User.order(email: :desc)
# SELECT "users".* FROM "users" ORDER BY "users"."email" DESC

Multiple columns can be passed this way, and they will be applied in the order specified.

User.order(:name, email: :desc)
# SELECT "users".* FROM "users" ORDER BY "users"."name" ASC, "users"."email" DESC


Strings are passed directly to the database, allowing you to specify simple SQL expressions.

This could be a source of SQL injection, so only strings composed of plain column names and simple function(column_name) expressions with optional ASC/DESC modifiers are allowed.

# SELECT "users".* FROM "users" ORDER BY name

User.order('name DESC')
# SELECT "users".* FROM "users" ORDER BY name DESC

User.order('name DESC, email')
# SELECT "users".* FROM "users" ORDER BY name DESC, email


If you need to pass in complicated expressions that you have verified are safe for the database, you can use Arel.

User.order(Arel.sql('end_date - start_date'))
# SELECT "users".* FROM "users" ORDER BY end_date - start_date

Custom query syntax, like JSON columns for Postgres, is supported in this way.

# SELECT "users".* FROM "users" ORDER BY payload->>'kind'
# File activerecord/lib/active_record/relation/query_methods.rb, line 425
def order(*args)
  check_if_method_has_arguments!(__callee__, args) do


Allows preloading of args, in the same way that includes does:

# SELECT "posts".* FROM "posts" WHERE "posts"."user_id" IN (1, 2, 3)
# File activerecord/lib/active_record/relation/query_methods.rb, line 221
def preload(*args)
  check_if_method_has_arguments!(__callee__, args)

readonly(value = true)

Sets readonly attributes for the returned relation. If value is true (default), attempting to update a record will result in an error.

users = User.readonly
=> ActiveRecord::ReadOnlyRecord: User is marked as readonly
# File activerecord/lib/active_record/relation/query_methods.rb, line 1001
def readonly(value = true)


Use to indicate that the given table_names are referenced by an SQL string, and should therefore be JOINed in any query rather than loaded separately. This method only works in conjunction with includes. See includes for more details.

User.includes(:posts).where(" = 'foo'")
# Doesn't JOIN the posts table, resulting in an error.

User.includes(:posts).where(" = 'foo'").references(:posts)
# Query now knows the string references posts, so adds a JOIN
# File activerecord/lib/active_record/relation/query_methods.rb, line 254
def references(*table_names)
  check_if_method_has_arguments!(__callee__, table_names)


Replaces any existing order defined on the relation with the specified order.

User.order('email DESC').reorder('id ASC') # generated SQL has 'ORDER BY id ASC'

Subsequent calls to order on the same relation will be appended. For example:

User.order('email DESC').reorder('id ASC').order('name ASC')

generates a query with 'ORDER BY id ASC, name ASC'.

# File activerecord/lib/active_record/relation/query_methods.rb, line 471
def reorder(*args)
  check_if_method_has_arguments!(__callee__, args) do


Allows you to change a previously set select statement., :body)
# SELECT `posts`.`title`, `posts`.`body` FROM `posts`, :body).reselect(:created_at)
# SELECT `posts`.`created_at` FROM `posts`

This is short-hand for unscope(:select).select(fields). Note that we're unscoping the entire select statement.

# File activerecord/lib/active_record/relation/query_methods.rb, line 332
def reselect(*args)
  check_if_method_has_arguments!(__callee__, args)


Reverse the existing order clause on the relation.

User.order('name ASC').reverse_order # generated SQL has 'ORDER BY name DESC'
# File activerecord/lib/active_record/relation/query_methods.rb, line 1190
def reverse_order


Allows you to change a previously set where condition for a given attribute, instead of appending to that condition.

Post.where(trashed: true).where(trashed: false)
# WHERE `trashed` = 1 AND `trashed` = 0

Post.where(trashed: true).rewhere(trashed: false)
# WHERE `trashed` = 0

Post.where(active: true).where(trashed: true).rewhere(trashed: false)
# WHERE `active` = 1 AND `trashed` = 0

This is short-hand for unscope(where: conditions.keys).where(conditions). Note that unlike reorder, we're only unscoping the named conditions – not the entire where statement.

# File activerecord/lib/active_record/relation/query_methods.rb, line 773
def rewhere(conditions)
  scope = spawn
  where_clause = scope.build_where_clause(conditions)

  scope.unscope!(where: where_clause.extract_attributes)
  scope.where_clause += where_clause


Works in two unique ways.

First: takes a block so it can be used just like Array#select. { |m| m.field == value }

This will build an array of objects from the database for the scope, converting them into an array and iterating through them using Array#select.

Second: Modifies the SELECT statement for the query so that only certain fields are retrieved:
# => [#<Model id: nil, field: "value">]

Although in the above example it looks as though this method returns an array, it actually returns a relation object and can have other query methods appended to it, such as the other methods in ActiveRecord::QueryMethods.

The argument to the method can also be an array of fields., :other_field, :and_one_more)
# => [#<Model id: nil, field: "value", other_field: "value", and_one_more: "value">]

You can also use one or more strings, which will be used unchanged as SELECT fields.'field AS field_one', 'other_field AS field_two')
# => [#<Model id: nil, field: "value", other_field: "value">]

If an alias was specified, it will be accessible from the resulting objects:'field AS field_one').first.field_one
# => "value"

Accessing attributes of an object that do not have fields retrieved by a select except id will throw ActiveModel::MissingAttributeError:
# => ActiveModel::MissingAttributeError: missing attribute: other_field
# File activerecord/lib/active_record/relation/query_methods.rb, line 304
def select(*fields)
  if block_given?
    if fields.any?
      raise ArgumentError, "`select' with block doesn't take arguments."

    return super()

  check_if_method_has_arguments!(__callee__, fields, "Call `select' with at least one field.")

strict_loading(value = true)

Sets the returned relation to strict_loading mode. This will raise an error if the record tries to lazily load an association.

user = User.strict_loading.first
=> ActiveRecord::StrictLoadingViolationError
# File activerecord/lib/active_record/relation/query_methods.rb, line 1016
def strict_loading(value = true)


Checks whether the given relation is structurally compatible with this relation, to determine if it's possible to use the and and or methods without raising an error. Structurally compatible is defined as: they must be scoping the same model, and they must differ only by where (if no group has been defined) or having (if a group is present).

Post.where("id = 1").structurally_compatible?(Post.where("author_id = 3"))
# => true

Post.joins(:comments).structurally_compatible?(Post.where("id = 1"))
# => false
# File activerecord/lib/active_record/relation/query_methods.rb, line 831
def structurally_compatible?(other)


Deduplicate multiple values.

# File activerecord/lib/active_record/relation/query_methods.rb, line 1231
def uniq!(name)
  if values = @values[name]
    values.uniq! if values.is_a?(Array) && !values.empty?


Removes an unwanted relation that is already defined on a chain of relations. This is useful when passing around chains of relations and would like to modify the relations without reconstructing the entire chain.

User.order('email DESC').unscope(:order) == User.all

The method arguments are symbols which correspond to the names of the methods which should be unscoped. The valid arguments are given in VALID_UNSCOPING_VALUES. The method can also be called with multiple arguments. For example:

User.order('email DESC').select('id').where(name: "John")
    .unscope(:order, :select, :where) == User.all

One can additionally pass a hash as an argument to unscope specific :where values. This is done by passing a hash with a single key-value pair. The key should be :where and the value should be the where value to unscope. For example:

User.where(name: "John", active: true).unscope(where: :name)
    == User.where(active: true)

This method is similar to except, but unlike except, it persists across merges:

    == User.order('email')

    == User.all

This means it can be used in association definitions:

has_many :comments, -> { unscope(where: :trashed) }
# File activerecord/lib/active_record/relation/query_methods.rb, line 524
def unscope(*args)
  check_if_method_has_arguments!(__callee__, args)


Returns a new relation, which is the result of filtering the current relation according to the conditions in the arguments.

where accepts conditions in one of several formats. In the examples below, the resulting SQL is given as an illustration; the actual query generated may be different depending on the database adapter.


A single string, without additional arguments, is passed to the query constructor as an SQL fragment, and used in the where clause of the query.

Client.where("orders_count = '2'")
# SELECT * from clients where orders_count = '2';

Note that building your own string from user input may expose your application to injection attacks if not done properly. As an alternative, it is recommended to use one of the following methods.


If an array is passed, then the first element of the array is treated as a template, and the remaining elements are inserted into the template to generate the condition. Active Record takes care of building the query to avoid injection attacks, and will convert from the ruby type to the database type where needed. Elements are inserted into the string in the order in which they appear.

User.where(["name = ? and email = ?", "Joe", ""])
# SELECT * FROM users WHERE name = 'Joe' AND email = '';

Alternatively, you can use named placeholders in the template, and pass a hash as the second element of the array. The names in the template are replaced with the corresponding values from the hash.

User.where(["name = :name and email = :email", { name: "Joe", email: "" }])
# SELECT * FROM users WHERE name = 'Joe' AND email = '';

This can make for more readable code in complex queries.

Lastly, you can use sprintf-style % escapes in the template. This works slightly differently than the previous methods; you are responsible for ensuring that the values in the template are properly quoted. The values are passed to the connector for quoting, but the caller is responsible for ensuring they are enclosed in quotes in the resulting SQL. After quoting, the values are inserted using the same escapes as the Ruby core method Kernel::sprintf.

User.where(["name = '%s' and email = '%s'", "Joe", ""])
# SELECT * FROM users WHERE name = 'Joe' AND email = '';

If where is called with multiple arguments, these are treated as if they were passed as the elements of a single array.

User.where("name = :name and email = :email", { name: "Joe", email: "" })
# SELECT * FROM users WHERE name = 'Joe' AND email = '';

When using strings to specify conditions, you can use any operator available from the database. While this provides the most flexibility, you can also unintentionally introduce dependencies on the underlying database. If your code is intended for general consumption, test with multiple database backends.


where will also accept a hash condition, in which the keys are fields and the values are values to be searched for.

Fields can be symbols or strings. Values can be single values, arrays, or ranges.

User.where(name: "Joe", email: "")
# SELECT * FROM users WHERE name = 'Joe' AND email = ''

User.where(name: ["Alice", "Bob"])
# SELECT * FROM users WHERE name IN ('Alice', 'Bob')

User.where(created_at: ( -
# SELECT * FROM users WHERE (created_at BETWEEN '2012-06-09 07:00:00.000000' AND '2012-06-10 07:00:00.000000')

In the case of a belongs_to relationship, an association key can be used to specify the model if an ActiveRecord object is used as the value.

author = Author.find(1)

# The following queries will be equivalent:
Post.where(author: author)
Post.where(author_id: author)

This also works with polymorphic belongs_to relationships:

treasure = Treasure.create(name: 'gold coins')
treasure.price_estimates << PriceEstimate.create(price: 125)

# The following queries will be equivalent:
PriceEstimate.where(estimate_of: treasure)
PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: treasure)


If the relation is the result of a join, you may create a condition which uses any of the tables in the join. For string and array conditions, use the table name in the condition.

User.joins(:posts).where("posts.created_at < ?",

For hash conditions, you can either use the table name in the key, or use a sub-hash.

User.joins(:posts).where("posts.published" => true)
User.joins(:posts).where(posts: { published: true })

no argument

If no argument is passed, where returns a new instance of WhereChain, that can be chained with WhereChain#not, WhereChain#missing, or WhereChain#associated.

Chaining with WhereChain#not:

User.where.not(name: "Jon")
# SELECT * FROM users WHERE name != 'Jon'

Chaining with WhereChain#associated:

# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# WHERE "authors"."id" IS NOT NULL

Chaining with WhereChain#missing:

# SELECT "posts".* FROM "posts"
# LEFT OUTER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# WHERE "authors"."id" IS NULL

blank condition

If the condition is any blank-ish object, then where is a no-op and returns the current relation.

# File activerecord/lib/active_record/relation/query_methods.rb, line 745
def where(*args)
  if args.empty?
  elsif args.length == 1 && args.first.blank?


Alias for: excluding