编辑:
您试图在最后一行中显示$id;但是您在php代码中是在哪里设置的?
试试这个:
$con = mysqli_connect("localhost","DB_NAME","PWD");
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
mysqli_select_db($con,"DB") or die ("no database");
$sql="SET @update_ID := 0;
UPDATE TABLE_234 SET PLAYERNAME = PETER, ID = (SELECT @update_ID := ID)
WHERE PLAYERNAME IS NULL
LIMIT 1;
SELECT @update_ID as ID";
if (mysqli_multi_query($con,$sql))
{
do
{
// Store first result set
if ($result=mysqli_store_result($con))
{
while ($row=mysqli_fetch_row($result))
{
$ID=$row[0];
}
}
}
while (mysqli_next_result($con));
}
echo "ID=" . $ID;
mysqli_close($con);