結合3選擇語句和按時間戳排序

Question

我有3個mysql語句，每個語句給出不同的結果集，我想代表所有從按timestamp desc排序的查詢中收集的所有結果。

例如：如果採購訂單在產品之前有時間戳，那麼他在採購訂單中的物品應該在產品之前。
我該怎麼做，併發送了3個結果集合的排序結果。我真的很感謝任何幫助。感謝您的提前。

$query=mysql_query("select * from products order by timestamp desc ;"); 
$numrows = mysql_num_rows($query); 
if ($numrows!=0) 
{ 
    $rows = array(); 
    while($r = mysql_fetch_assoc($query)) { 
     $rows[] = $r; 
    } 
} 
echo json_encode($rows); 

$query2=mysql_query("select * from user_purchased order by timestamp desc ;"); 
$numrows2 = mysql_num_rows($query2); 
if ($numrows2!=0) 
{ 
    $rows2 = array(); 
    while($r2 = mysql_fetch_assoc($query2)) { 
     $rows2[] = $2r; 
    } 
} 
echo json_encode($rows2); 

$query3=mysql_query("select * from delivery order by timestamp desc ;"); 
$numrows3 = mysql_num_rows($query3); 
if ($numrows3!=0) 
{ 
    $rows3 = array(); 
    while($r3 = mysql_fetch_assoc($query3)) { 
     $rows3[] = $r3; 
    } 
} 
echo json_encode($rows3); 

Answer 1

爲了將所有的數據和日期倒序排序，你可以使用一個子查詢與UNION ALL並從所有3個表結合聯合國下令結果...然後命令由時間戳下降的記錄。下面是一個例子。但是，如果它們都具有不同的字段名稱並且字段名稱的數量不同，則可以創建虛擬字段名稱以創建一致的信息。它在下面的編輯中被描述。

爲了簡單起見，我們假設所有表的構造如下

+-------+-----------+------+-----+-------------------+-------+ 
| Field | Type  | Null | Key | Default   | Extra | 
+-------+-----------+------+-----+-------------------+-------+ 
| id | int(11) | YES |  | NULL    |  | 
| ts | timestamp | NO |  | CURRENT_TIMESTAMP |  | 
+-------+-----------+------+-----+-------------------+-------+ 

讓我們來看看每個表中的虛擬數據。

產品

mysql> select * from products; 
+------+---------------------+ 
| id | ts     | 
+------+---------------------+ 
| 1 | 2014-03-26 04:39:06 | 
| 4 | 2014-03-26 04:40:05 | 
+------+---------------------+ 

User_Purchased

mysql> select * from user_purchased; 
+------+---------------------+ 
| id | ts     | 
+------+---------------------+ 
| 2 | 2014-03-26 04:39:19 | 
| 5 | 2014-03-26 04:40:00 | 
+------+---------------------+ 

交貨

mysql> select * from delivery; 
+------+---------------------+ 
| id | ts     | 
+------+---------------------+ 
| 3 | 2014-03-26 04:39:28 | 
| 6 | 2014-03-26 04:39:38 | 
+------+---------------------+ 

PHP

<?php 
$db = mysqli_connect('host','usr','pwd'); 
mysqli_select_db($db,'yourdb'); 
$data = mysqli_query($db, " 
    select * from 
    (
     select 'products' as tbl, id, ts from products 
     union all 
     select 'purchased' as tbl, id, ts from user_purchased 
     union all 
     select 'delivered' as tbl, id, ts from delivery 
    ) a 
    order by ts desc 
    " 
); 

echo "tablename\tid\ttime\n"; 
foreach ($data as $row) { 
    echo "{$row['tbl']}\t{$row['id']}\t{$row['ts']}\n"; 
} 
?> 

輸出

tablename  id  time 
products  4  2014-03-26 04:40:05 
purchased  5  2014-03-26 04:40:00 
delivered  6  2014-03-26 04:39:38 
delivered  3  2014-03-26 04:39:28 
purchased  2  2014-03-26 04:39:19 
products  1  2014-03-26 04:39:06 

編輯

假設產品表有字段標識，產品名稱，productnumber。 購買了id，productid，purchaseate。 交付有id，purchaseid，deliverydate。

你可以通過做這樣的事情在每個查詢中的所有字段組合，然後排序上mytimestamp：

select 
    'products' as tbl, pdt_id, productname as pdt_productname, productnumber as pdt_productnumber, 
    '-' as pur_id, '-' as pur_productid, '-' as pur_purchasedate, 
    '-' as del_id, '-' as del_purchaseid, '-' as del_deliverydate, 
    ts as mytimestamp 
from products 
union all 
select 
    'purchased' as tbl, '-' as pdt_id, '-' as pdt_productname, '-' as pdt_productnumber, 
    id as pur_id, productid as pur_productid, purchasedate as pur_purchasedate, 
    '-' as del_id, '-' as del_purchaseid, '-' as del_deliverydate, 
    ts as mytimestamp 
from purchased 
union all 
select 
    'delivered' as tbl, '-' as pdt_id, '-' as pdt_productname, '-' as pdt_productnumber, 
    '-' as pur_id, '-' as pur_productid, '-' as pur_purchasedate, 
    id as del_id, purchaseid as del_purchaseid, deliverydate as del_deliverydate, 
    ts as mytimestamp 
from delivered