Method: ActiveRecord::ConnectionAdapters::IBM_DB2_I5#columns_for_distinct

Defined in:
lib/active_record/connection_adapters/ibm_db_adapter.rb

#columns_for_distinct(columns, orders) ⇒ Object

T009: IBM DB requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 3227

def columns_for_distinct(columns, orders)
  order_columns = orders.map{ |s|
      # Convert Arel node to string
      s = s.to_sql unless s.is_a?(String)
      # Remove any ASC/DESC modifiers
      s.gsub(/\s+(ASC|DESC)\s*(NULLS\s+(FIRST|LAST)\s*)?/i, '')
    }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
  [columns, *order_columns].join(', ')
end