左外连接错误导致MYSQL

我正在使用MySQL连接。我有两个表，我需要一个连接。第一个表包含所有房地产属性，第二个表包含向该属性添加收藏的用户。现在我想显示登录用户喜欢的图标的所有属性。我在MySQL中编写下面的查询。但是这个查询返回所有记录。左外连接错误导致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

还有一个问题。该查询返回我复制属性如果超过一个用户喜欢的

添加相同的属性下面是我从API获得最终输出时，我使用这个查询

{ 
    "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 
     } 
    ] 
}

来源

2016-02-02 Azad chouhan

你可以在表格/模式中显示样本数据吗？ – Stidgeon

在这种情况下，LEFT OUTER join将从左表中返回*所有记录*（仅受WHERE子句限制） - property_for_sale和property_for_rent。它应该是一个INNER连接吗？ – user2864740

@Stidgeon请检查我添加结果 –

我想你错过限制当前登录的用户。将它添加到ON条款（:currentUserId占位符）：

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

来源

2016-02-02 07:27:52

中添加的记录，因为它正在工作 –

如果你想显示两个用户，那么使用下面的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：如果你不想显示多个逗号分隔用户然后不使用group_concat函数，那么你的查询只会给你第一个用户。

来源

2016-02-02 07:33:35

左外连接错误导致MYSQL

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