添加「和」和「或」子句通過rails查詢界面查詢

我想通過Rails查詢界面運行下面的查詢，但無法翻譯我的邏輯。查詢是添加「和」和「或」子句通過rails查詢界面查詢

Select f.* from feeds f 
Left join feed_items fi on fi.id = f.feedable_id 
where 
    f.feedable_type in ('Homework', 'Datesheet') 
    and 
    (
    (fi.assignable_type = 'Level' and assignable_id IN (1)) or 
    (fi.assignable_type = 'Student' and assignable_id IN (1)) or 
    (fi.assignable_type = 'Section' and assignable_id IN (1)) 
)

場景：

我收到以下PARAMS散列包含將動態在我的查詢

{"page"=>"1", "limit"=>"2", "type_filter"=>["Homework", "Datesheet"], "assignable_filter"=>{"Student"=>"[2]", "Section"=>"[1]", "Level"=>"[1]"}}

到目前爲止，加入過濾器，我的動作我做了什麼正在加入表格並添加where子句的類型過濾器，但不知道如何動態添加assignable_filters。這裏是我的Rails代碼，options是params在下面的代碼

def get_feeds(options) 
    base = Feed.includes(:feed_item) 
    base = add_type_filters base, options 
    base = add_assignable_filters base, options 
    format_response base, options 
end 

def add_type_filters(base, options) 
    type_filter = options[:type_filter] 
    if !type_filter.nil? and type_filter.length > 0 
     base = base.where('feedable_type IN (?)', options[:type_filter]) 
    end 
    base 
end 

def add_assignable_filters(base, options) 
    assignable_filter = options[:assignable_filter] 
    if !assignable_filter.nil? 
     assignable_filter.each do |key, value| 
     # code for adding filters combined with or conditions 
     end 
     # wrap the or conditions and join them with an and in main where clause 
    end 
    base 
end

P.S我用導軌5

來源

2017-07-31 Umair Abid

我注意到的第一件事：是不是feed和feed_items（一對多關係？）。如果是'Feed.includes（：feed_items）'是正確的。 – haffla

在這裏您可以看到如何在Rails5中執行OR查詢：https://stackoverflow.com/questions/32753168/rails-5-activerecord-or-query – haffla

@haffla其一對一關聯 –

有動態生成的查詢沒有直接的方法。我必須構建解決問題的字符串。我目前的解決方案是

def get_feeds(options) 
    params_hash = {} 
    type_filters = add_type_filters options, params_hash 
    assignable_filters = add_assignable_filters options, params_hash 

    where = type_filters 
    where = where ? "#{where} and (#{assignable_filters})" : assignable_filters 

    base = Feed.eager_load(:feed_item).where(where, params_hash) 
    format_response base, options 
end 

def add_type_filters(options, params_hash) 
    type_filter = options[:type_filter] 
    type_filter_sql = nil 
    if !type_filter.nil? and type_filter.length > 0 
     type_filter_sql = 'feeds.feedable_type in (:type_filter)' 
     params_hash[:type_filter] = type_filter 
    end 
    type_filter_sql 
end 

def add_assignable_filters(options, params_hash) 
    assignable_filter_sql = [] 
    assignable_filter = options[:assignable_filter] 
    if !assignable_filter.nil? 
     assignable_filter.each do |key, value| 
     assignable_filter_sql.push("(feed_items.assignable_type = '#{key}' and feed_items.assignable_id IN (:#{key}))") 
     params_hash[key.to_sym] = JSON.parse(value) 
     end 
    end 
    assignable_filter_sql.join(' or ') 
end

來源

2017-08-01 05:14:41

添加「和」和「或」子句通過rails查詢界面查詢

回答

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