左外連接錯誤導致MYSQL

我正在使用MySQL連接。我有兩個表，我需要一個連接。第一個表包含所有房地產屬性，第二個表包含向該屬性添加收藏的用戶。現在我想顯示登錄用戶喜歡的圖標的所有屬性。我在MySQL中編寫下面的查詢。但是這個查詢返回所有記錄。左外連接錯誤導致MYSQL

SELECT a. * , b.property_id AS fav, b.user_id 
FROM `property_for_sale` a 
LEFT OUTER JOIN `cpo_favourite_property` b ON a.id = b.property_id 
WHERE a.property_type = 'Commercial' 
UNION 
SELECT a. * , b.property_id AS fav, b.user_id 
FROM `property_for_rent` a 
LEFT OUTER JOIN `cpo_favourite_property` b ON a.id = b.property_id 
WHERE a.property_type = 'Commercial' 
ORDER BY id DESC

還有一個問題。該查詢返回我複製屬性如果超過一個用戶喜歡的

添加相同的屬性下面是我從API獲得最終輸出時，我使用這個查詢

{ 
    "success": "1", 
    "user": [ 
     { 
      "id": "1266", 
      "date": "2016-01-25", 
      "date_25_days": "2016-02-19", 
      "date_30_days": "2016-02-24", 
      "time": "04:47:40 PM", 
      "user_name": "anil123", 
      "fileupload": "186_39151.jpg", 
      "image2": "Null", 
      "image3": "Null", 
      "image4": "Null", 
      "description": "gg", 
      "fav": "1266", 
      "user_id": "19" 
     }, 
     { 
      "id": "1266", 
      "date": "2016-01-25", 
      "date_25_days": "2016-02-19", 
      "date_30_days": "2016-02-24", 
      "time": "04:47:40 PM", 
      "user_name": "anil123", 
      "fileupload": "186_39151.jpg", 
      "image2": "Null", 
      "image3": "Null", 
      "image4": "Null", 
      "description": "gg", 
      "fav": "1266", 
      "user_id": "480" 
     }, 
     { 
      "id": "1144", 
      "date": "2015-12-07", 
      "date_25_days": "2016-01-01", 
      "date_30_days": "2016-01-06", 
      "time": "05:45:30 PM", 
      "user_name": "Realtyup Estate Agency", 
      "fileupload": "464_IMG-20140812-WA0063.jpg", 
      "image2": "821_IMG-20140812-WA0064.jpg", 
      "image3": "Null", 
      "image4": "Null", 
      "description": "Commercial showroom at Mansa Devi Complex Sector 4 Panchkula.Ground/basement/first/second fully constructed floors.Ample parking.Corner three side open.Well suited for any kind of business establishment", 
      "fav": null, 
      "user_id": null 
     }, 
     { 
      "id": "625", 
      "date": "2016-02-01", 
      "date_25_days": "2016-02-25", 
      "date_30_days": "2016-03-01", 
      "time": "02:25:40 AM", 
      "user_name": "", 
      "fileupload": "Null", 
      "image2": "Null", 
      "image3": "Null", 
      "image4": "Null", 
      "description": "VjD7Gu http://www.FyLitCl7Pf7kjQdDUOLQOuaxTXbj5iNG.com", 
      "fav": null, 
      "user_id": null 
     }, 
     { 
      "id": "624", 
      "date": "2016-01-31", 
      "date_25_days": "2016-02-25", 
      "date_30_days": "2016-03-01", 
      "time": "05:44:10 PM", 
      "user_name": "", 
      "fileupload": "Null", 
      "image2": "Null", 
      "image3": "Null", 
      "image4": "Null", 
      "description": "DIMgVX http://www.FyLitCl7Pf7kjQdDUOLQOuaxTXbj5iNG.com", 
      "fav": null, 
      "user_id": null 
     }, 
     { 
      "id": "623", 
      "date": "2016-01-31", 
      "date_25_days": "2016-02-25", 
      "date_30_days": "2016-03-01", 
      "time": "12:59:54 PM", 
      "user_name": "", 
      "fileupload": "Null", 
      "image2": "Null", 
      "image3": "Null", 
      "image4": "Null", 
      "description": "2lx6j8 http://www.FyLitCl7Pf7kjQdDUOLQOuaxTXbj5iNG.com", 
      "fav": null, 
      "user_id": null 
     } 
    ] 
}

來源

2016-02-02 Azad chouhan

你可以在表格/模式中顯示樣本數據嗎？ – Stidgeon

在這種情況下，LEFT OUTER join將從左表中返回*所有記錄*（僅受WHERE子句限制） - property_for_sale和property_for_rent。它應該是一個INNER連接嗎？ – user2864740

@Stidgeon請檢查我添加結果 –

我想你錯過限制當前登錄的用戶。將它添加到ON條款（:currentUserId佔位符）：

SELECT a. * , b.property_id AS fav, b.user_id 
FROM `property_for_sale` a 
LEFT OUTER JOIN `cpo_favourite_property` b ON a.id = b.property_id AND b.user_id = :currentUserId 
WHERE a.property_type = 'Commercial' 
UNION 
SELECT a. * , b.property_id AS fav, b.user_id 
FROM `property_for_rent` a 
LEFT OUTER JOIN `cpo_favourite_property` b ON a.id = b.property_id AND b.user_id = :currentUserId 
WHERE a.property_type = 'Commercial' 
ORDER BY id DESC

來源

2016-02-02 07:27:52

中添加的記錄，因爲它正在工作 –

如果你想顯示兩個用戶，那麼使用下面的query

SELECT a. * , b.property_id AS fav, group_concat(b.user_id) 
FROM `property_for_sale` a 
LEFT OUTER JOIN `cpo_favourite_property` b ON a.id = b.property_id 
WHERE a.property_type = 'Commercial' 
group by a.id 
UNION 
SELECT a. * , b.property_id AS fav, group_concat(b.user_id) 
FROM `property_for_rent` a 
LEFT OUTER JOIN `cpo_favourite_property` b ON a.id = b.property_id 
WHERE a.property_type = 'Commercial' 
group by a.id 
ORDER BY id DESC

注意：如果你不想顯示多個逗號分隔用戶然後不使用group_concat函數，那麼你的查詢只會給你第一個用戶。

來源

2016-02-02 07:33:35

左外連接錯誤導致MYSQL

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