/ Ruby on Rails
/
method

add_limit_offset!

add_limit_offset!(sql, options)
public

No documentation available.

# File activerecord/lib/active_record/connection_adapters/db2_adapter.rb, line 94
        def add_limit_offset!(sql, options)
          if options[:limit] and !options[:limit].nil?
            # "FETCH FIRST 0 ROWS ONLY" is not allowed, so we have
            # to use a cheap trick.
            if options[:limit] == 0
              if sql =~ /WHERE/i
                sql.sub!(/WHERE/i, 'WHERE 1 = 2 AND ')
              elsif
                sql =~ /ORDER\s+BY/i
                sql.sub!(/ORDER\s+BY/i, 'WHERE 1 = 2 ORDER BY')
              else
                sql << 'WHERE 1 = 2'
              end
            else
              sql << " FETCH FIRST #{options[:limit]} ROWS ONLY" 
            end
          end
          if options[:offset] and !options[:offset].nil?
            raise ArgumentError, ':offset option is not yet supported!'
          end
        end

1Note

Why gsub!

benissimo ยท Apr 14, 2011

I notice other adapters use sql.sub!, not sql.gsub! and in fact I had trouble with adding the limit parameter to any query involving nested selects. Replacing sql.gsub! with sql.sub! solved that problem for me. Has anyone else had a similar experience with this method?

In other words, replace: sql.gsub!(/SELECT/i, 'SELECT B.* FROM (SELECT A., row_number() over () AS internal$rownum FROM (SELECT') With: sql.sub!(/SELECT/i, 'SELECT B. FROM (SELECT A.*, row_number() over () AS internal$rownum FROM (SELECT')