Question

我正在建立一个网站，用户可以选择一个出租房产，有两个字段，他们可以选择，家具和宠物。两个选择框中的选项均为“是”和“否”。

<select name="furnished">
  <option value="">
  <option value="yes">Yes</option>
  <option value="no">No</option>
</select>

<select name="pets">
  <option value="">
  <option value="yes">Yes</option>
  <option value="no">No</option>
</select>

我正在根据用户在这些字段中选择的内容编写SQL语句。

$sql = 'SELECT *
       FROM properties
       WHERE num_bedrooms >= ' . $_GET['num_bedrooms'] . 
       ' AND num_bathrooms >= ' . $_GET['num_bathrooms'];

if($_GET['furnished'] == 'yes') { //if the furnished is set to yes
  $sql .= ' AND furnished = "yes" OR furnished = "partially"';
} else if($_GET['furnished'] == 'no') { //if the furnished is set to no
  $sql .= ' AND furnished = "no" OR furnished = "description"';
} 

if($_GET['pets'] == 'yes') { //if the pets is set to yes
  $sql .= ' AND pets = "yes" OR pets = "cats" OR pets = "dogs"';
} else if($_GET['pets'] == 'no') { //if the pets is set to no
  $sql .= ' AND pets = "no" OR pets = "description"';
}

如果用户选择“是”，我希望它显示所有提供的属性（是）或部分提供（部分）。如果用户选择“否”，我希望它显示所有未提供的属性（否）或具有特殊描述（描述）的属性。

如果用户对宠物选择“是”，我希望它显示允许所有宠物的所有属性（是）或仅允许猫（猫）或仅允许狗（狗）的属性。如果用户选择“否”，我希望它显示所有不允许宠物的属性（否）或具有特殊描述（描述）的属性。

例如，如果用户在“家具”上选择“是”，在“宠物”上选择“是”，则这是输出的SQL语句：

SELECT * FROM properties 
WHERE num_bedrooms >= 1 
AND num_bathrooms >= 1 
AND furnished = "yes" OR furnished = "partially" 
AND pets = "yes" OR pets = "cats" OR pets = "dogs"

问题在于它目前会在where子句中返回符合家具或宠物要求的结果，而我需要它返回符合where子句中所提供的和宠物要求的结果。

因此，它将返回一个结果，其中说明“家具”设置为“是”，并且宠物设置为“否”。如何将所有结果返回到带有设置的设置为是和宠物设置为是？

我的SQL语句出了什么问题？

Answer 1

AND位于运算符优先级OR之前，因此您的查询类似于

SELECT * FROM properties 
WHERE 
(num_bedrooms >= 1 AND num_bathrooms >= 1 AND furnished = "yes")
OR (furnished = "partially" AND pets = "yes")
OR pets = "cats" 
OR pets = "dogs"

这不是你所期望的。尝试

SELECT * FROM properties 
WHERE num_bedrooms >= 1 
AND num_bathrooms >= 1 
AND (furnished = "yes" OR furnished = "partially")
AND (pets = "yes" OR pets = "cats" OR pets = "dogs")

甚至更好

SELECT * FROM properties 
WHERE num_bedrooms >= 1 
AND num_bathrooms >= 1 
AND furnished IN ("yes", "partially")
AND pets IN ("yes", "cats", "dogs")

您不应该SELECT *尝试命名您需要的列！

Answer 2

将parens放在各种OR'事物上。

$sql .= ' AND (furnished = "yes" OR furnished = "partially")';

$sql .= ' AND (pets = "yes" OR pets = "cats" OR pets = "dogs")';

等等。

我的SQL语句出了什么问题？

2 个答案: