Running a stored procedure that populates a temporary table and then selecting from the temporary table

I have a stored procedure that populates a global temporary table.

CREATE GLOBAL TEMPORARY TABLE temptable
(
...
)
ON COMMIT DELETE ROWS;

I want to run the stored procedure and then select the rows added to the temporary table.

$conn = oci_connect(...);
$sql = "BEGIN POPULATETEMPTABLE END;"
$stmt = oci_parse($conn, $sql);
oci_execute($stmt);
oci_free_statement($stmt);

$sql = "SELECT ... FROM temptable";
$stmt = oci_parse($conn, $sql);
oci_execute($stmt);

while ($row = oci_fetch_assoc($stmt))
{
    ...
}

oci_free_statement($stmt);
oci_close($conn);

That code fetches no rows. So I decided to put the select in the same round trip to the database:

$conn = oci_connect(...);
$sql = "
    BEGIN POPULATETEMPTABLE END;
    SELECT ... FROM temptable
"
$stmt = oci_parse($conn, $sql);
oci_execute($stmt);

while ($row = oci_fetch_assoc($stmt))
{
    ...
}

oci_free_statement($stmt);
oci_close($conn);

And that gives me error:

PLS-00103: Encountered the symbol "SELECT"

If I put the SELECT inside the BEGIN ... END; then I get this error:

PLS-00428: an INTO clause is expected in this SELECT statement

How do I run a stored procedure that populates a temporary table and then select from it in PHP?

It works in SQL Developer, just not in PHP.

Using:

PHP 8.1.4
Oracle 19.0.0.0.0

The first issue is because oci_execute() commits by default, so any rows inserted by the call to POPULATETEMPTABLE are cleaned up by the ON COMMIT DELETE ROWS; definition.

Fix this by changing to:

$sql = "BEGIN POPULATETEMPTABLE END;"
$stmt = oci_parse($conn, $sql);
oci_execute($stmt, OCI_NO_AUTO_COMMIT);

The secondary issue about putting the SELECT in the PL/SQL block is because this is invalid PL/SQL. Use a REF CURSOR or an IMPLICIT RESULT SET. See the OCI8 doc or The Underground PHP and Oracle Manual