我的SQL語句有什麼問題？

Question

我正在做一個網站，用戶可以選擇一個出租物業，有兩個領域，他們可以選擇，傢俱和寵物。在兩個選擇框中的選項是是和否。

<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> 

我正在編寫基於用戶在這些字段中選擇的SQL語句。

$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"'; 
} 

如果用戶是選擇有傢俱，我希望它顯示配（是），或者是部分傢俱（部分）的所有屬性。如果用戶選擇否，我希望它顯示所有未提供的屬性（否）或具有特殊描述（描述）的屬性。

如果用戶爲寵物選擇是，我希望它顯示允許所有寵物（是）或只允許貓（貓）或只允許狗（狗）的所有屬性。如果用戶選擇否，我希望它顯示所有不允許寵物的屬性（否）或具有特殊描述（描述）的屬性。

作爲一個例子，這是輸出的SQL語句，如果用戶選擇上提供的是的是的寵物：

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" 

的問題是，它現在將返回滿足裝飾或寵物的任何結果在where條款中的要求，而我需要它返回符合where條款中的傢俱和寵物要求的結果。

所以它現在會返回一個結果，說有Furnished設置爲yes，寵物設置爲no。 我怎樣才能返回所有結果與傢俱設置爲是和寵物設置爲是？

我的SQL語句有什麼問題？

Answer 1

AND來運算符優先級OR之前，讓您的查詢讀起來就像

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" 

這是不太你所期望的。嘗試

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") 

你不應該做SELECT *嘗試命名您需要的列！

Answer 2

把parens放在各種各樣的OR的東西。

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

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

等等。