Shell scripting-Unable to use output variable

I am trying to use the value of 'P' in the second SQL procedure however it doesnt take the value. Please suggest.

P=`sqlplus -s $OraInfo <<!EOF
   SET ECHO ON
   SET SERVEROUTPUT ON SIZE 1000000
   SET LINE 900
   SET WRAP ON
   SET HEADING OFF
   SET TRIMOUT ON
   SET TRIMSPOOL ON
   select i_rea_enrl from NTA_ENRL WHERE I_ENRL_ASG='$f2';  
    print 
    exit;
!EOF`

echo $P >> $LOG_FILE

Q=\'$ShellName\'
`sqlplus -s $OraInfo <<-! >> $LOG_FILE
    SET ECHO ON
    SET SERVEROUTPUT ON SIZE 1000000
    SET LINE 900;
    SET WRAP ON;
    exec STAPROC.STA_NTA_ENRL_PP7_PKG.ADD_TO_STAGE($P,'PP7','$f2');
    print
    exit;
!EOF`