如何從產品表中創建5個價格範圍

Question

我有一個產品表，其中包含價格和主類別的列。

我想查詢我的數據庫發現有一個給定的類別（或所有類別）的價格範圍內。這次價格範圍將被分成價格範圍適當數量，即0〜£££5 5£10等等

我不能讓我的周圍如何做到這一點頭;我需要使用php來做到這一切嗎？爲了澄清，我希望最終結束，無論列出哪個類別，我都可以展示大概相同數量的產品的4個價格區間。我不能讓我的心靈軟弱周圍:(

Answer 1

對於每個類別的最低和最高價格：

SELECT category, min(price) as min_price, max(price) as max_price 
from Products 
Group BY category 

對於範圍直接在查詢中，你可以做這樣的事情

SELECT 
    category, 
    SUM(CASE WHEN price BETWEEN 0 AND 5 THEN 1 ELSE 0 END) as zero-five, 
    SUM(CASE WHEN price BETWEEN 5 AND 10 THEN 1 ELSE 0 END) as five-ten, 
    ... 
from Products 
Group BY category 

產量

Category zero-five five-ten 
Cat1  2   4 
Cat2  3   6 

或

SELECT category, range, count(*) 
FROM (
    SELECT 
     category, 
     CASE WHEN price BETWEEN 0 to 5 THEN '0-5' 
      WHEN price BETWEEN 5 to 10 THEN '5-10' 
      ... 
      ELSE '10+' 
     END as range 
    FROM products 
) 
group by category, range 

產量

Category range count 
Cat1  0-5 2  
Cat1  5-10 4  
Cat1  10+ 0 
Cat2  0-5 3  
Cat2  5-10 6  
Cat2  10+ 0 

Answer 2

不知道你的表結構，但這會搶獨特的價格在你的產品表：

select distinct price from products order by price desc; 

從這裏，我可能會開始使用PHP 。究竟如何，你更喜歡它們分解價格進入組

Answer 3

$sql = " 
SELECT P1.category as category, min(P1.price) as min_price, max(P2.price) as max_price 
FROM Products P1 join Products P2 on P1.category=P2.category 
Group BY category 
"; 
<table width="300" border="1"> 
<tr> 
<td><b>category</b></td> 
<td><b>min_price</b></td> 
<td><b>max_price</b></td> 
</tr> 
$result = mysql_query($sql); 
while($row = mysql_fetch_array($result)) 
{ 
//print data 
?> 
<tr> 
<td><? echo $row['category']; ?></td> 
<td><? echo $row['min_price']; ?></td> 
<td><? echo $row['max_price']; ?></td> 
</tr> 
<? 
} 
?>