Php 链接Mysql查询以进行插入

仅当两个条件为真时，我才尝试插入一行。我想在一份声明中这样做。我的桌子看起来像：

             [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                      

是否有一种执行sql的方法：

LIRFU=用户的最后插入行=从表中选择*，其中userId=$userId ORDER BY timestamp DESC LIMIT 1

如果LIRFU.type=0，则插入一行$userId、$locationId、1。 如果LIRFU.type=1和LIRFU.locationId！=则插入一行$userId、$locationId、0$locationId。 让我们调用您的表，用户类型

下面的语句用于在LIRFU.type=0时插入包含示例数据5,19,1的行：

您可以通过用？替换数据，将其转换为PHP中的准备语句

如果LIRFU.type=1且LIRFU.locationId！=1，那么下面的语句将插入一行，其中包含示例数据5,19,019:

用PHP编写时也有同样的想法：

$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();

$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();

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;

$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();