rails_sql_client.rb

#!/usr/bin/env ruby

env_rb = ['../config/environment.rb', 'config/environment.rb'].detect { |file| File.exist? file }
raise 'Run this from rails root or a subdirectory.' unless env_rb

require File.expand_path(env_rb)

if ARGV[0] =~ /^-[cexq]$/
  ARGV.shift
  sql_in = ARGV.join(' ')
elsif ARGV[0] =~ /^-f?/
  ARGV.shift
  sql_in = ARGF.read
elsif ARGV[0] == '-h'
  puts "#{$PROGRAM_NAME} [<sql file>]"
  puts "#{$PROGRAM_NAME} -q <query>"
  puts "#{$PROGRAM_NAME} -f <file>"
  puts "#{$PROGRAM_NAME} -"
  puts "#{$PROGRAM_NAME}"
  exit
end

loop do
  print 'sql> ' unless sql_in
  sql = sql_in || gets.strip rescue (puts; exit)
  break if sql == 'q'

  sql.split(';').each do |query|
    next if query.blank?

    puts
    puts query

    results = ActiveRecord::Base.connection.select_all(query).to_a
    next if results.blank?

    columns = {}
    results.first.each_key do |k|
      columns[k] = [results.map { |g| g[k].size }.max, k.titleize.size].max
    end

    puts "+-#{columns.map { |_k, v| '-' * v }.join('-+-')}-+"
    puts "| #{columns.map { |k, v| k.ljust(v) }.join(' | ')} |"
    puts "+-#{columns.map { |_k, v| '-' * v }.join('-+-')}-+"
    results.each do |row|
      puts "| #{columns.keys.map { |k| row[k].to_s.ljust(columns[k]) }.join(' | ')} |"
    end
    puts "+-#{columns.map { |_k, v| '-' * v }.join('-+-')}-+"
    puts
  rescue => e
    puts e
  end
  break if sql_in.present?
end