method

distinct

Ruby on Rails latest stable (v7.1.3.2) - 0 notes - Class: ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

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What's this?

Method deprecated or moved

This method is deprecated or moved on the latest stable version. The last existing version (v3.2.13) is shown here.

These similar methods exist in v7.1.3.2:

distinct(columns, orders) public

Returns a SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.

PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column.

distinct("posts.id", "posts.created_at desc")

Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1105
      def distinct(columns, orders) #:nodoc:
        return "DISTINCT #{columns}" if orders.empty?

        # Construct a clean list of column names from the ORDER BY clause, removing
        # any ASC/DESC modifiers
        order_columns = orders.collect { |s| s.gsub(/\s+(ASC|DESC)\s*(NULLS\s+(FIRST|LAST)\s*)?/, '') }
        order_columns.delete_if { |c| c.blank? }
        order_columns = order_columns.zip((0...order_columns.size).to_a).map { |s,i| "#{s} AS alias_#{i}" }

        "DISTINCT #{columns}, #{order_columns * ', '}"
      end

distinct

Related methods

Method deprecated or moved