链接Mysql查询插入

Question

我只想在两个条件为真时插入一行。我想在一个声明中这样做。我的表如下所示：

   [Table]     
id, userId, locationId, type, timestamp    
---------------------------------------    
1 5 19 0 2017-03-28 03:05:48     
2 5 19 1 2017-03-29 00:57:57      

是否有执行SQL的方式：

LIRFU =上次插入行对于用户= SELECT * FROM Table WHERE userId = $userId ORDER BY timestamp DESC LIMIT 1。

• 插入一行($userId, $locationId, 1)如果LIRFU.type = 0。
• 插入一行($userId, $locationId, 0) if 。

Answer 1

让我们打电话给你的表，User_Types。

这里插入样本数据（5,19,1）如果LIRFU.type = 0一行语句：

INSERT INTO User_Types (userId, locationId, type) 
SELECT @userId:=5, 19, 1 from dual 
WHERE (SELECT type FROM User_Types WHERE userId = @userId ORDER BY timestamp DESC LIMIT 1) = 0; 

您可以通过?替换数据制作成一份准备好的声明这PHP。

$stmt = $db->prepare("INSERT INTO User_Types (userId, locationId, type) SELECT @userId:=?, ?, 1 from dual WHERE (SELECT type FROM User_Types WHERE userId = @userId ORDER BY timestamp DESC LIMIT 1) = 0"); 

$stmt->bind_param('ii', $user_id, $location_id); 
//if LIRFU.type = 0 

$stmt->execute(); 

---

这里的插入，如果LIRFU.type = 1 AND LIRFU.locationId != 19与样本数据的行（5,19,0）声明：

INSERT INTO User_Types (userId, locationId, type) 
SELECT @userId:=5, @locationId:=19, 0 from dual 
WHERE (SELECT type FROM User_Types WHERE userId = @userId ORDER BY timestamp DESC LIMIT 1) = 1 
AND (SELECT locationId FROM User_Types WHERE userId = @userId ORDER BY timestamp DESC LIMIT 1) <> @locationId; 

，当它在PHP，准备同样的想法：

$stmt = $db->prepare("INSERT INTO User_Types (userId, locationId, type) SELECT @userId:=?, @locationId:=?, 0 from dual WHERE (SELECT type FROM User_Types WHERE userId = @userId ORDER BY timestamp DESC LIMIT 1) = 1 AND (SELECT locationId FROM User_Types WHERE userId = @userId ORDER BY timestamp DESC LIMIT 1) <> @locationId"); 

$stmt->bind_param('ii', $user_id, $location_id); 
//if LIRFU.type = 1 and LIRFU.locationId != $location_id 

$stmt->execute();