Help with the SQL inline statement solution used in a PHP program

Help with a SQL inline statement in a PHP program
The following is the PHP program code, but the call does not have any content, there is no error message
$pid = $_get[' pid '];
PID is not empty, the call record
if (!empty ($pid)) {
$sql = "Select Pd.pid, Pd.providerid, Pd.item, Pd.update, Pd.price, Pd.minorder, Pd.imglink, Pv.id, Pv.company from Price_ DB as PD ".
"INNER join providers as PV".
"On (Pd.providerid = pv.id) where pd.pid= $pid";
Require_once ('.. /.. /conn.php ');
Echo $sql;
$result = Mysqli_query ($conn, $sql) or Die ("$sql
" . Mysql_error ()); The SQL statement executes here
$row = Mysqli_fetch_array ($result);
$item = $row [item];
$update = $row [UPDATE];
$price = $row [Price];
$minOrder = $row [Minorder];
$imglink = $row [Imglink];

The following is the Echo $sql statement
Select Pd.pid, Pd.providerid, Pd.item, Pd.update, Pd.price, Pd.minorder, Pd.imglink, Pv.id, Pv.company from price_db as PD Inner join providers as PV on (Pd.providerid = pv.id) where pd.pid=4
Mysql_error () No error, determined that the problem is in red in the SQL inline statement shown, please help to see

------Solution--------------------
Take your SQL statement and take a look at the MySQL terminal to see what the reaction is ...
------Solution--------------------
$result = Mysqli_query ($conn, $sql) or Die ("$sql
" . Mysql_error ());
You are mistaken here.
echo Mysqli_error ($conn);
------Solution--------------------
There are no errors, and there may be no results that meet the criteria
------Solution--------------------
First you that this SQL select Pd.pid, Pd.providerid, Pd.item, Pd.update, Pd.price, Pd.minorder, Pd.imglink, Pv.id, Pv.company from Pric e_db as PD inner join providers as PV on (Pd.providerid = pv.id) where pd.pid=4 go to database execution have no results?
There's a result, that's what's wrong, it's empty.
------Solution--------------------
Check the character type of the MySQL table field corresponding to the $pid, and if it is char, add '
------Solution--------------------
discuss
The following is the PHP program code, but the call does not have any content, there is no error message
$pid = $_get[' pid '];
PID is not empty, the call record
if (!empty ($pid)) {
$sql = "Select Pd.pid, Pd.providerid, Pd.item, Pd.update, Pd.price, Pd.minorder, Pd.imglink, Pv.id, Pv.company ...

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