Problem with productnames, MySQL

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#MySQL 5.7.12
#please drop objects you've created at the end of the script 
#or check for their existance before creating
#'\\' is a delimiter

DROP TABLE buget;

CREATE TABLE buget
    (`clientid` int, `date` varchar(10), `quant` int, `product` varchar(8), `client` varchar(5), `place` varchar(5), `price` int)
;
    
INSERT INTO buget
    (`clientid`, `date`, `quant`, `product`, `client`, `place`, `price`)
VALUES
    (1, '2016-01-10', 1, 'product1', 'anna', 'Italy', 100),
    (1, '2016-04-12', 2, 'product2', 'anna', 'Italy', 400),
    (1, '2017-01-10', 1, 'product3', 'anna', 'Italy', 100),
    (1, '2017-04-12', 2, 'product4', 'anna', 'Italy', 700),
    (2, '2016-01-10', 1, 'product1', 'peter', 'Italy', 300),
    (2, '2016-04-12', 2, 'product2', 'peter', 'Italy', 300),
    (2, '2017-01-10', 1, 'product3', 'peter', 'Italy', 300),
    (2, '2017-04-12', 2, 'product4', 'peter', 'Italy', 900)
;

Select
   m1.clientid,
   m1.cyear,
   m1.product cproduct,
   m0.product pproduct,
   m0.pyear,
   m1.sum csum,
   m0.sum psum,
   (
      m1.sum - m0.sum
   )
   diff 
from
   (
      select
         clientid,
         product,
         cyear,
         sum 
      from
         (
            select
               clientid,
                 product,
               year(date) cyear,
               sum(price) sum 
            from
               buget 
            group by
               clientid,
               cyear
         )
         T 
      where
         cyear = year(curdate())
   )
   m1,
   (
(
      select
         clientid, product, pyear, sum 
      from
         (
            select
               clientid,
             product,
               year(date) pyear,
               sum(price) sum 
            from
               buget 
            group by
               clientid,
               pyear
         )
         T 
      where
         pyear = 
         (
            year(curdate())
         )
          - 1) m0
   )
where
   m1.clientid = m0.clientid


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