Printing single result from db2 query in php - php

Question

I'm running a query on db2 in a php script, which is running successfully but I can't get it to echo the actual ID of the record I've selected. It does echo my success statement showing it ran successfully but I need the actual sessionid for comparison in another query.
Here I'm selecting the record, executing the query and checking for execution, but I'm also trying to use fetch_row and result to return the single selected ID:
$latest_result = "SELECT MAX(SESSIONID) as SESSIONID FROM session";
$prepareSessionMax = odbc_prepare($DB2Conn, $latest_result);
$executeSessionMax = odbc_execute($prepareSessionMax);
while(odbc_fetch_row($executeSessionMax)){
$maxResult = odbc_result($executeSessionMax, "SESSIONID");
echo $maxResult;
}
How can I return the sessionID into a variable properly from db2?

Answer 1

You are passing the wrong parameter to the odbc_fetch_row() as $executeSessionMax is either a True or False depending on successful execution.
$latest_result = "SELECT MAX(SESSIONID) as SESSIONID FROM session";
$prepareSessionMax = odbc_prepare($DB2Conn, $latest_result);
$executeSessionMax = odbc_execute($prepareSessionMax);
while(odbc_fetch_row($prepareSessionMax )){
// correction here ^^^^^^^^^^^^^^^^^^
$maxResult = odbc_result($executeSessionMax, "SESSIONID");
echo $maxResult;
}
You could recode as this specially as a MAX() will only ever return one row so the while loop is not needed either.
$latest_result = "SELECT MAX(SESSIONID) as SESSIONID FROM session";
$prepareSessionMax = odbc_prepare($DB2Conn, $latest_result);
if (odbc_execute($prepareSessionMax)) {
odbc_fetch_row($prepareSessionMax );
$maxResult = odbc_result($executeSessionMax, "SESSIONID");
echo $maxResult;
// if echo gets lost try writing to a file
error_log("maxResult = $maxResult", 3, "my-errors.log");
} else {
// something went wrong in the execute
}
You could also try
$latest_result = "SELECT MAX(SESSIONID) as SESSIONID FROM session";
$result = odbc_exec($DB2Conn, $latest_result);
$rows = odbc_fetch_object($result);
echo $row->SESSIONID;
$maxResult = $row->SESSIONID;