我有一个现有的 Rails 2.3.x 应用程序，它使用以下代码块对给定数据范围的 4 列数据进行求和。
results = connection.execute(<<-SQL)
SELECT sum(total_hours), sum(expected_hours), sum(total_billable), sum(expected_billable)
FROM `timesheets`
WHERE (`timesheets`.`week_starting` BETWEEN '#{Date.today.beginning_of_year}' AND '#{Date.today.monday}')
SQL
total_hours, expected_hours, total_billable, expected_billable = results.fetch_row.map(&:to_f).map(&:to_d)
当我升级到 Rails 3 和 mysql2 时，fetch_row 方法不再存在，因此我认为这是使用 ARel 整理此查询的好机会。
有人知道如何使用 ARel 执行此查询吗？
最佳答案
以模块化“构建器”风格编写，允许重构为可重用范围:
Timesheet.where('week_starting >= ?', Date.today.beginning_of_year).
where('week_starting < ?', Date.today.monday).
select('SUM(total_hours) as total_hours').
select('SUM(expected_hours) as expected_hours').
select('SUM(total_billable) as total_billable').
select('SUM(total_hours) as expected_billable')
关于ruby-on-rails - 使用 ARel 整理查询，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10134167/