使用相同ID＃

Question

我想从表称为address_contact我用的是代码的最后ID＃3个表中选择行的比较快的方式是：

$result = mysql_query("SELECT id FROM address_contact ORDER BY lastUpdate DESC LIMIT 1") 
or die(mysql_error()); 
$row = mysql_fetch_array($result); 
$id = .$row['id']; 

现在我想关闭连接，并打开一个新的，然后获取所有数据的使用，我们只是得到了ID＃以下3个表：

Table 1: address_address 
Table 2: address_contact 
Table 3: address_email 

所以它会是这个样子？？？

$result = mysql_query("SELECT address_contact.id,address_contact.lastname,address_contact.firstname,address_contact.primaryAddType,address_address.id,address_address.phone1,address_address.phone2,address_address.line2,address_email.id,address_email.email 
FROM address_address 
LEFT JOIN address_contact ON address_address.id=address_contact.id 
LEFT JOIN address_email ON address_address.id=address_email.id     
WHERE address_contact.id = ".$id) 

但是必须有一个更简单/更快的方法来做到这一点？

Answer 1

您可以使用子查询来查找ID一个SQL语句做到这一点。

SELECT 
    address_contact.id, 
    address_contact.lastname, 
    address_contact.firstname, 
    address_contact.primaryAddType, 
    address_address.id, 
    address_address.phone1, 
    address_address.phone2, 
    address_address.line2, 
    address_email.id, 
    address_email.email 
FROM 
    address_address 
    LEFT JOIN address_contact ON address_address.id = address_contact.id 
    LEFT JOIN address_email ON address_address.id = address_email.id     
    WHERE address_contact.id = (
    SELECT id FROM address_contact ORDER BY lastUpdate DESC LIMIT 1 
) 

Answer 2

如果这个ID是你只插入一个全新的纪录，你应该使用msyql_last_insert_id()功能，保证您获得最后插入这个特定的脚本/数据库手柄一样。你的方法受制于种族条件 - 如果某个OTHER脚本在这个脚本的后面插入了一个插入，你将得到该脚本的ID，而不是你的。

话虽这么说，你会更好做

SELECT MAX（ID）FROM yourtable

，而不是由/限制版本的订货。这样做效率更高。

的基本代码序列是：

INSERT INTO yourtable .... 
SELECT @id := last_insert_id(); 
SELECT ... FROM yourtable WHERE id = @id; 

Answer 3

为什么不使用单一查询

SELECT address_contact.id,address_contact.lastname,address_contact.firstname,address_contact.primaryAddType,address_address.id,address_address.phone1,address_address.phone2,address_address.line2,address_email.id,address_email.email 
FROM address_address 
LEFT JOIN address_contact ON address_address.id=address_contact.id 
LEFT JOIN address_email ON address_address.id=address_email.id     
ORDER BY address_contact.lastUpdate DESC 
LIMIT 1