爲什麼這個Ruby Squeel（PostgreSQL）調用返回nil，當它顯然不是？

我有一個搜索頁面，允許用戶根據GPA和運動狀態等標準搜索運動員。當只使用一個搜索過濾器時，PostgreSQL返回正確的答案。當使用多個搜索過濾器時，只有在兩個搜索過濾器中使用相同的統計信息時，它纔會起作用。例如，如果我搜索「GPA> 3」和「GPA == 4」，它會返回相應的運動員。如果我做了「GPA> 3」和「ACT> 20」（兩者在同一名運動員中都是如此），它什麼都不返回（空陣列）。爲什麼這個Ruby Squeel（PostgreSQL）調用返回nil，當它顯然不是？

對於整個頁面引用，這裏是@conditions的樣子（它轉換成代碼，而不是一個散列所以循環可以遍歷數組，但你得到的要點）：

{ 
"0"=>{"category"=>"1", "stat_type_id"=>"22", "predicate"=>"Greater Than", 
"q"=>"2", "type"=>"stat"}, 

"1"=>{"category"=>"1", "stat_type_id"=>"2", 
"predicate"=>"Greater Than", "q"=>"10", "type"=>"stat"} 
}

下面是代碼（Squeel語法）：

def query 
    relation = Athlete.listed.for_sport(self.sport) 

    return relation if @conditions.blank? 

    @conditions = @conditions.map { |k, v| v } if @conditions.is_a?(Hash) 

    debugger 

    @conditions.each do |condition| 
    case condition[:type] 
    when "stat" 
     if !condition[:q].eql?("") 
     relation = case condition[:predicate] 
     when /less than/i 
      relation.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.lt (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     when /greater than/i 
      relation.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.gt (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     when /equal to/i 
      relation.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.eq (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     when /not equal to/i 
      relation.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.not_eq (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     end 
     end 
    when "academic" 
     relation 
    when "social" 
     relation 
    end 
    end 

    relation 
end

我已經包含空兩個PostgreSQL的通話紅寶石調試抓住（我使用Squeel，一個Ruby包裝對PostgreSQL）。如果你在兩個調用中向下滾動，你會看到第一個和第二個調用是相同的，但第二個調用有一個額外的AND（並遵循與第一個相同的格式，應該可以正常工作）。

呼叫1（一個參數）：

SELECT "users"."id"         AS t0_r0, 
     "users"."name"        AS t0_r1, 
     "users"."first_name"       AS t0_r2, 
     "users"."last_name"       AS t0_r3, 
     "users"."facebook_id"       AS t0_r4, 
     "users"."access_token"      AS t0_r5, 
     "users"."birthday"       AS t0_r6, 
     "users"."gender"        AS t0_r7, 
     "users"."device_token"      AS t0_r8, 
     "users"."current_city"      AS t0_r9, 
     "users"."hometown"       AS t0_r10, 
     "users"."relationship_status"     AS t0_r11, 
     "users"."avatar_file_name"     AS t0_r12, 
     "users"."avatar_content_type"     AS t0_r13, 
     "users"."avatar_file_size"     AS t0_r14, 
     "users"."avatar_updated_at"     AS t0_r15, 
     "users"."email"        AS t0_r16, 
     "users"."encrypted_password"     AS t0_r17, 
     "users"."reset_password_token"    AS t0_r18, 
     "users"."reset_password_sent_at"    AS t0_r19, 
     "users"."remember_created_at"     AS t0_r20, 
     "users"."sign_in_count"      AS t0_r21, 
     "users"."current_sign_in_at"     AS t0_r22, 
     "users"."last_sign_in_at"      AS t0_r23, 
     "users"."current_sign_in_ip"     AS t0_r24, 
     "users"."last_sign_in_ip"      AS t0_r25, 
     "users"."authentication_token"    AS t0_r26, 
     "users"."created_at"       AS t0_r27, 
     "users"."updated_at"       AS t0_r28, 
     "users"."time_zone"       AS t0_r29, 
     "users"."username"       AS t0_r30, 
     "users"."middle_name"       AS t0_r31, 
     "users"."primary_sport_id"     AS t0_r32, 
     "users"."state"        AS t0_r33, 
     "users"."high_school"       AS t0_r34, 
     "users"."phone"        AS t0_r35, 
     "users"."user_type_id"      AS t0_r36, 
     "users"."agreed_to_terms_and_conditions"  AS t0_r37, 
     "users"."agreed_to_information_integrity"  AS t0_r38, 
     "users"."agreed_to_content_responsibility" AS t0_r39, 
     "users"."account_type_id"      AS t0_r40, 
     "users"."social_score"      AS t0_r41, 
     "users"."recruit_year"      AS t0_r42, 
     "users"."college_major"      AS t0_r43, 
     "users"."secondary_sport_id"     AS t0_r44, 
     "users"."handedness"       AS t0_r45, 
     "users"."checkdin_id"       AS t0_r46, 
     "users"."allow_twitter_sync"     AS t0_r47, 
     "users"."allow_facebook_sync"     AS t0_r48, 
     "users"."head_coach"       AS t0_r49, 
     "users"."head_coach_email"     AS t0_r50, 
     "users"."has_recruited_others"    AS t0_r51, 
     "users"."customer_id"       AS t0_r52, 
     "users"."last_4_digits"      AS t0_r53, 
     "users"."removed_from_listing"    AS t0_r54, 
     "users"."slug"        AS t0_r55, 
     "users"."college_minor"      AS t0_r56, 
     "users"."type"        AS t0_r57, 
     "users"."billing_expiration_month"   AS t0_r58, 
     "users"."billing_expiration_year"    AS t0_r59, 
     "users"."billing_name"      AS t0_r60, 
     "users"."billing_address"      AS t0_r61, 
     "users"."billing_city"      AS t0_r62, 
     "users"."billing_state"      AS t0_r63, 
     "users"."billing_zip"       AS t0_r64, 
     "users"."college_id"       AS t0_r65, 
     "users"."agreed_to_age_requirements"   AS t0_r66, 
     "users"."primary_sport_primary_position_id" AS t0_r67, 
     "users"."secondary_sport_primary_position_id" AS t0_r68, 
     "users"."recruit_status_id"     AS t0_r69, 
     "users"."active_flag"       AS t0_r70, 
     "users"."public"        AS t0_r71, 
     "invitations"."id"       AS t1_r0, 
     "invitations"."sender_id"      AS t1_r1, 
     "invitations"."role_id"      AS t1_r2, 
     "invitations"."to"       AS t1_r3, 
     "invitations"."accepted_at"     AS t1_r4, 
     "invitations"."token"       AS t1_r5, 
     "invitations"."created_at"     AS t1_r6, 
     "invitations"."updated_at"     AS t1_r7, 
     "invitations"."current_state"     AS t1_r8, 
     "invitations"."requester_id"     AS t1_r9, 
     "invitations"."user_type"      AS t1_r10, 
     "invitations"."type"       AS t1_r11 
FROM "users" 
     INNER JOIN "stats" 
       ON "stats"."athlete_id" = "users"."id" 
     LEFT OUTER JOIN "invitations" 
        ON "invitations"."requester_id" = "users"."id" 
WHERE "users"."removed_from_listing" = 'f' 
     AND "users"."type" IN ('Athlete') 
     AND (("invitations"."current_state" IN ('accepted') 
       OR "invitations"."current_state" IS NULL)) 
     AND (users.primary_sport_id = 13 
       OR users.secondary_sport_id = 13) 
     AND (("stats"."stat_type_id" = 22 
       AND "stats"."value" > '2.0'))

結果是一個運動員。

召喚2（兩個參數）：

第二次調用然而，返回[]，但應該是一樣的運動員......

SELECT "users"."id"         AS t0_r0, 
     "users"."name"        AS t0_r1, 
     "users"."first_name"       AS t0_r2, 
     "users"."last_name"       AS t0_r3, 
     "users"."facebook_id"       AS t0_r4, 
     "users"."access_token"      AS t0_r5, 
     "users"."birthday"       AS t0_r6, 
     "users"."gender"        AS t0_r7, 
     "users"."device_token"      AS t0_r8, 
     "users"."current_city"      AS t0_r9, 
     "users"."hometown"       AS t0_r10, 
     "users"."relationship_status"     AS t0_r11, 
     "users"."avatar_file_name"     AS t0_r12, 
     "users"."avatar_content_type"     AS t0_r13, 
     "users"."avatar_file_size"     AS t0_r14, 
     "users"."avatar_updated_at"     AS t0_r15, 
     "users"."email"        AS t0_r16, 
     "users"."encrypted_password"     AS t0_r17, 
     "users"."reset_password_token"    AS t0_r18, 
     "users"."reset_password_sent_at"    AS t0_r19, 
     "users"."remember_created_at"     AS t0_r20, 
     "users"."sign_in_count"      AS t0_r21, 
     "users"."current_sign_in_at"     AS t0_r22, 
     "users"."last_sign_in_at"      AS t0_r23, 
     "users"."current_sign_in_ip"     AS t0_r24, 
     "users"."last_sign_in_ip"      AS t0_r25, 
     "users"."authentication_token"    AS t0_r26, 
     "users"."created_at"       AS t0_r27, 
     "users"."updated_at"       AS t0_r28, 
     "users"."time_zone"       AS t0_r29, 
     "users"."username"       AS t0_r30, 
     "users"."middle_name"       AS t0_r31, 
     "users"."primary_sport_id"     AS t0_r32, 
     "users"."state"        AS t0_r33, 
     "users"."high_school"       AS t0_r34, 
     "users"."phone"        AS t0_r35, 
     "users"."user_type_id"      AS t0_r36, 
     "users"."agreed_to_terms_and_conditions"  AS t0_r37, 
     "users"."agreed_to_information_integrity"  AS t0_r38, 
     "users"."agreed_to_content_responsibility" AS t0_r39, 
     "users"."account_type_id"      AS t0_r40, 
     "users"."social_score"      AS t0_r41, 
     "users"."recruit_year"      AS t0_r42, 
     "users"."college_major"      AS t0_r43, 
     "users"."secondary_sport_id"     AS t0_r44, 
     "users"."handedness"       AS t0_r45, 
     "users"."checkdin_id"       AS t0_r46, 
     "users"."allow_twitter_sync"     AS t0_r47, 
     "users"."allow_facebook_sync"     AS t0_r48, 
     "users"."head_coach"       AS t0_r49, 
     "users"."head_coach_email"     AS t0_r50, 
     "users"."has_recruited_others"    AS t0_r51, 
     "users"."customer_id"       AS t0_r52, 
     "users"."last_4_digits"      AS t0_r53, 
     "users"."removed_from_listing"    AS t0_r54, 
     "users"."slug"        AS t0_r55, 
     "users"."college_minor"      AS t0_r56, 
     "users"."type"        AS t0_r57, 
     "users"."billing_expiration_month"   AS t0_r58, 
     "users"."billing_expiration_year"    AS t0_r59, 
     "users"."billing_name"      AS t0_r60, 
     "users"."billing_address"      AS t0_r61, 
     "users"."billing_city"      AS t0_r62, 
     "users"."billing_state"      AS t0_r63, 
     "users"."billing_zip"       AS t0_r64, 
     "users"."college_id"       AS t0_r65, 
     "users"."agreed_to_age_requirements"   AS t0_r66, 
     "users"."primary_sport_primary_position_id" AS t0_r67, 
     "users"."secondary_sport_primary_position_id" AS t0_r68, 
     "users"."recruit_status_id"     AS t0_r69, 
     "users"."active_flag"       AS t0_r70, 
     "users"."public"        AS t0_r71, 
     "invitations"."id"       AS t1_r0, 
     "invitations"."sender_id"      AS t1_r1, 
     "invitations"."role_id"      AS t1_r2, 
     "invitations"."to"       AS t1_r3, 
     "invitations"."accepted_at"     AS t1_r4, 
     "invitations"."token"       AS t1_r5, 
     "invitations"."created_at"     AS t1_r6, 
     "invitations"."updated_at"     AS t1_r7, 
     "invitations"."current_state"     AS t1_r8, 
     "invitations"."requester_id"     AS t1_r9, 
     "invitations"."user_type"      AS t1_r10, 
     "invitations"."type"       AS t1_r11 
FROM "users" 
     INNER JOIN "stats" 
       ON "stats"."athlete_id" = "users"."id" 
     LEFT OUTER JOIN "invitations" 
        ON "invitations"."requester_id" = "users"."id" 
WHERE "users"."removed_from_listing" = 'f' 
     AND "users"."type" IN ('Athlete') 
     AND (("invitations"."current_state" IN ('accepted') 
       OR "invitations"."current_state" IS NULL)) 
     AND (users.primary_sport_id = 13 
       OR users.secondary_sport_id = 13) 
     AND (("stats"."stat_type_id" = 22 
       AND "stats"."value" > '2.0')) 
     AND (("stats"."stat_type_id" = 2 
       AND "stats"."value" > '10'))

知道爲什麼這是不工作？ Bumfuddled！

::::: UPDATE ::::: 通過執行以下固定它，它還是蠻快：

def query 
athletes = Athlete.listed.for_sport(self.sport) 
relation = athletes 

return relation if @conditions.blank? 

@conditions = @conditions.map { |k, v| v } if @conditions.is_a?(Hash) 

@conditions.each do |condition| 
    case condition[:type] 
    when "stat" 
    if !condition[:q].eql?("") 
     relation = case condition[:predicate] 
     when /less than/i 
     athletes.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.lt (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     when /greater than/i 
     athletes.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.gt (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     when /equal to/i 
     athletes.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.eq (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     when /not equal to/i 
     athletes.joins{stats}.where{(stats.stat_type_id.eq condition[:stat_type_id]) & (stats.value.not_eq (StatType.where(:id => condition[:stat_type_id]).first.display_as_decimal == true ? condition[:q].to_f.to_s : condition[:q].to_i.to_s))} 
     end 
    end 
    when "academic" 
    relation 
    when "social" 
    relation 
    end 
end 

relation 
end

來源

2013-03-18 trevorhinesley

那些呈現的查詢實在太長，無法閱讀。他們需要更好的格式。 – tadman 2013-03-18 19:08:01

我認爲一個mod爲我格式化了，非常感謝！我遇到了問題。 – trevorhinesley 2013-03-18 19:24:45

你的第二個查詢，像這樣結尾的WHERE子句：

AND (("stats"."stat_type_id" = 22 
       AND "stats"."value" > '2.0')) 
AND (("stats"."stat_type_id" = 2 
       AND "stats"."value" > '10'))

stat_type_id不能等於2和22在同一時間。你將需要第二個加盟統計表所示：

INNER JOIN "stats" 
       ON "stats"."athlete_id" = "users"."id" 
INNER JOIN "stats" AS s2 
       ON "s2"."athlete_id" = "users"."id" 
(...) 
AND (("stats"."stat_type_id" = 22 
       AND "stats"."value" > '2.0')) 
AND (("s2"."stat_type_id" = 2 
       AND "s2"."value" > '10'))

如果你不想做dynamicaly加入的替代是一個子查詢，如：

SELECT athlete_id 
FROM stats 
WHERE 
("stats"."stat_type_id" = 22 
       AND "stats"."value" > '2.0') 
OR ("s2"."stat_type_id" = 2 
       AND "s2"."value" > '10') 
GROUP BY athlete_id 
HAVING COUNT(*)=<the number of parameters you want to filter by>

這將返回滿足所有運動員該標準如此與表格的其餘部分相連接。

來源

2013-03-18 20:47:51

嗯，我理解這個問題@Jakub Kania，我只是不確定我在循環中要做些什麼。有什麼建議麼？謝謝！請記住，它仍然需要以這樣的方式運行，即BOTH過濾器必須對運動員返回是真實的，它不應該返回過濾器1爲真的所有運動員以及過濾器2爲真的所有運動員 – trevorhinesley 2013-03-18 20:58:18

Might已經找到了一種方式，謝謝..回到有點哈哈.. – trevorhinesley 2013-03-18 21:10:27

@Robokid兩次加入同一張桌子就是這樣。它也可以通過子查詢來完成，但這會過於複雜。 – 2013-03-18 21:19:22

爲什麼這個Ruby Squeel（PostgreSQL）調用返回nil，當它顯然不是？

回答

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