Module: WillPaginate::ActiveRecord::BaseMethods

Included in:
WillPaginate::ActiveRecord
Defined in:
lib/will_paginate/active_record.rb

Instance Method Summary collapse

Instance Method Details

#paginate_by_sql(sql, options) ⇒ Object

Wraps find_by_sql by simply adding LIMIT and OFFSET to your SQL string based on the params otherwise used by paginating finds: page and per_page.

Example:

@developers = Developer.paginate_by_sql ['select * from developers where salary > ?', 80000],
                       :page => params[:page], :per_page => 3

A query for counting rows will automatically be generated if you don't supply :total_entries. If you experience problems with this generated SQL, you might want to perform the count manually in your application.


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# File 'lib/will_paginate/active_record.rb', line 197

def paginate_by_sql(sql, options)
  pagenum  = options.fetch(:page) { raise ArgumentError, ":page parameter required" } || 1
  per_page = options[:per_page] || self.per_page
  total    = options[:total_entries]

  WillPaginate::Collection.create(pagenum, per_page, total) do |pager|
    query = sanitize_sql(sql.dup)
    original_query = query.dup
    oracle = self.connection.adapter_name =~ /^(oracle|oci$)/i

    # add limit, offset
    if oracle
      query = <<-SQL
        SELECT * FROM (
          SELECT rownum rnum, a.* FROM (#{query}) a
          WHERE rownum <= #{pager.offset + pager.per_page}
        ) WHERE rnum >= #{pager.offset}
      SQL
    else
      query << " LIMIT #{pager.per_page} OFFSET #{pager.offset}"
    end

    # perfom the find
    pager.replace find_by_sql(query)

    unless pager.total_entries
      count_query = original_query.sub /\bORDER\s+BY\s+[\w`,\s.]+$/mi, ''
      count_query = "SELECT COUNT(*) FROM (#{count_query})"
      count_query << ' AS count_table' unless oracle      # perform the count query

      pager.total_entries = count_by_sql(count_query)
    end
  end
end