Question

我想更好的建议......更好地使用ruby功能。任何人都可以给我一个更好的解决方案来组装这个查询吗？

@conditions = ""
if(ratings["G"] == "1")
  @conditions += " 'G' "

end
if(ratings["PG"] == "1")
  @conditions += " OR rating = 'PG' "

end
if(ratings["PG-13"] == "1")
  @conditions += " OR rating = 'PG-13' "

end
if(ratings["R"] == "1")
  @conditions += " OR rating = 'R' "

end

@movies = Movie.where("rating = "+ @conditions)

return @movies

非常感谢你，

Answer 1

Movie.where(:rating => ratings.select({|k,v| v == "1"}).keys)

Answer 2

虽然@xdazz答案更清晰，但这种方式会返回所需的输出。

@conditions = ""
ratings.each do |k, v|
  @conditions << (@conditions.empty? ? "rating = '#{k}'" : " OR rating = '#{k}'") if v == "1"
end
@movies = Movie.where(@conditions)

修改

方法Hash＃keys只返回哈希的键。这可以通过以下方式说明：

p ratings.select { |k,v| v == "1" }.keys # => ["G", "PG", "PG-13", "R"] p ratings.select { |k,v| v == "1" } # => {"G"=>"1", "PG"=>"1", "PG-13"=>"1", "R"=>"1"}

虽然上面的方法会返回更像SQL的字符串：

p @conditions # => "rating = 'G' OR rating = 'PG' OR rating = 'PG-13' OR rating = 'R'"

最后，@ xdazz方法可以重写为以下内容，以便获得相同的输出：

p "rating = '" + ratings.select { |k,v| v == "1" }.keys.join("' OR rating = '") + "'" # => "rating = 'G' OR rating = 'PG' OR rating = 'PG-13' OR rating = 'R'"

编辑2： 为了清楚原始问题是否与Rails相关，@ xdazz答案是应该使用的答案。

Ruby在WHERE子句中使用带有多个选项的查询

2 个答案: