未验证 提交 89595aff 编写于 作者: R Rafael França 提交者: GitHub

Merge pull request #34562 from ruralocity/active-record-query-docs-improvement

Improve ActiveRecord::Querying documentation [ci skip]
......@@ -16,17 +16,17 @@ module Querying
delegate :pluck, :pick, :ids, to: :all
# Executes a custom SQL query against your database and returns all the results. The results will
# be returned as an array with columns requested encapsulated as attributes of the model you call
# this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in
# be returned as an array, with the requested columns encapsulated as attributes of the model you call
# this method from. For example, if you call <tt>Product.find_by_sql</tt>, then the results will be returned in
# a +Product+ object with the attributes you specified in the SQL query.
#
# If you call a complicated SQL query which spans multiple tables the columns specified by the
# If you call a complicated SQL query which spans multiple tables, the columns specified by the
# SELECT will be attributes of the model, whether or not they are columns of the corresponding
# table.
#
# The +sql+ parameter is a full SQL query as a string. It will be called as is, there will be
# no database agnostic conversions performed. This should be a last resort because using, for example,
# MySQL specific terms will lock you to using that particular database engine or require you to
# The +sql+ parameter is a full SQL query as a string. It will be called as is; there will be
# no database agnostic conversions performed. This should be a last resort because using
# database-specific terms will lock you into using that particular database engine, or require you to
# change your call if you switch engines.
#
# # A simple SQL query spanning multiple tables
......@@ -61,7 +61,9 @@ def find_by_sql(sql, binds = [], preparable: nil, &block)
# Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part.
# The use of this method should be restricted to complicated SQL queries that can't be executed
# using the ActiveRecord::Calculations class methods. Look into those before using this.
# using the ActiveRecord::Calculations class methods. Look into those before using this method,
# as it could lock you into a specific database engine or require a code change to switch
# database engines.
#
# Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
# # => 12
......
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