MySQL statement works in workbench but errors in PHP

The following sql code runs just fine in MySQL Workbench but returns

"string(228) "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'SELECT p2.this_year,year(p.PAID_DATE) as current_year,c1.s1,c2.p1,c3.p2,ly.last_' at line 6" in PHP.

I've searched for an answer to no avail. Wondering if anyone has any ideas. Thanks in advance.

$dbinfo = dbinfo();
$con = mysqli_connect($dbinfo['localhost'],$dbinfo['localuser'],$dbinfo['localpass'],$dbase);
if (!$con) die('Could not connect: ' . mysqli_error($con));

$sql = "
SET @startdate = DATE(CURDATE()- INTERVAL DAYOFYEAR(CURDATE())+1 DAY), @enddate = CURDATE(),
    @laststart = DATE_SUB(@startdate, INTERVAL 1 YEAR),
    @lastend = DATE_SUB(@enddate, INTERVAL 1 YEAR)
    ;

SELECT p2.this_year,year(p.PAID_DATE) as current_year,c1.s1,c2.p1,c3.p2,ly.last_year,
    lyc1.s1,lyc2.p1,lyc3.p2
FROM btb.payments as p

join (
    select CLIENTID,sum(TOTAL) this_year,PAID_DATE
    from btb.payments
    where PAID_DATE between @startdate and @enddate
) as p2

join (
    select id_no,count(SUMMER_PT1) S1 
    from btb.Client
    where SUMMER_PT1 <> ''
) as c1
    on c1.ID_NO = p.CLIENTID

join (
    select id_no,count(PART1) P1
    from btb.Client
    where PART1 <> ''
) as c2

join (
    select id_no,count(PART2) P2
    from btb.Client
    where PART2 <> ''
) as c3

join (
    SELECT CLIENTID,sum(TOTAL) as last_year
    FROM btb.payments
    where PAID_DATE between @laststart and @lastend
) as ly

join (
SELECT d.CLIENTID,d.SESSION,count(p.CLIENTID) s1
FROM btb.Details d
join btb.payments p
    on p.CLIENTID = d.CLIENTID
where p.PAID_DATE between @laststart and @lastend
    and d.year = year(@laststart)
    and d.SESSION = 'S1'
) as lyc1
    -- on c1.ID_NO = p.CLIENTID

join (
SELECT d.CLIENTID,d.SESSION,count(p.CLIENTID) p1
FROM btb.Details d
join btb.payments p
    on p.CLIENTID = d.CLIENTID
where p.PAID_DATE between @laststart and @lastend
    and d.year = year(@laststart)
    and d.SESSION = 'P1'
) as lyc2

join (
SELECT d.CLIENTID,d.SESSION,count(p.CLIENTID) p2
FROM btb.Details d
join btb.payments p
    on p.CLIENTID = d.CLIENTID
where p.PAID_DATE between @laststart and @lastend
    and d.year = year(@laststart)
    and d.SESSION = 'P2'
) as lyc3

where p.PAID_DATE between @startdate and @enddate
;";

$result = mysqli_query($con, $sql);
if($result === false) {
    var_dump(mysqli_error($con));
}
else {
    print_r(mysqli_num_rows($result));
}