Wrong results for complex query with subquery and window functions over decimal(12,4) column

MariaDB [test]> show create table t\G

*************************** 1. row ***************************

       Table: t

Create Table: CREATE TABLE `t` (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `cid` int(11) DEFAULT NULL,

  `d` datetime DEFAULT NULL,

  `c` decimal(12,4) DEFAULT NULL,

  PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=196592 DEFAULT CHARSET=latin1

1 row in set (0,000 sec)

MariaDB [test]> show create table tc\G

*************************** 1. row ***************************

       Table: tc

Create Table: CREATE TABLE `tc` (

  `id` int(11) NOT NULL,

  `cid` int(11) DEFAULT NULL,

  `d` datetime DEFAULT NULL,

  `c` decimal(12,4) DEFAULT NULL

) ENGINE=Columnstore DEFAULT CHARSET=latin1

1 row in set (0,000 sec)

MariaDB [test]> select count(*) from t;

+----------+

| count(*) |

+----------+

|   131072 |

+----------+

1 row in set (0,100 sec)

MariaDB [test]> delete from tc;

Query OK, 131072 rows affected (3,930 sec)

MariaDB [test]> insert into tc select * from t;

Query OK, 131072 rows affected (8,289 sec)

Records: 131072  Duplicates: 0  Warnings: 0

MariaDB [test]> pager md5sum

PAGER set to 'md5sum'

MariaDB [test]> select * from t order by id;

75092d9f7a63a7489c1f2ea5aea916aa  -

131072 rows in set (0,189 sec)

MariaDB [test]> select * from tc order by id;

75092d9f7a63a7489c1f2ea5aea916aa  -

131072 rows in set (0,963 sec)

MariaDB [test]> select cust, week_d, mpp_sum , stddev(mpp_sum) over (partition by cust) as mpp_stdev , avg(mpp_sum) over (partition by cust) as mpp_mean , sum(mpp_sum) over (partition by cust) as glob_mpp_sum,  count(mpp_sum) over (partition by cust) as glob_mpp_count from  (select distinct cid as cust,  week(d) as week_d , sum(c) over (partition by cid, week(d)) as mpp_sum  from t where year(d) = '2018') as inside where cust = 0 and week_d = 0;

+------+--------+-------------+------------+-----------------+--------------+----------------+

| cust | week_d | mpp_sum     | mpp_stdev  | mpp_mean        | glob_mpp_sum | glob_mpp_count |

+------+--------+-------------+------------+-----------------+--------------+----------------+

|    0 |      0 | 103715.8800 | 0.00000000 | 103715.88000000 |  103715.8800 |              1 |

+------+--------+-------------+------------+-----------------+--------------+----------------+

1 row in set (0,096 sec)

MariaDB [test]> select cust, week_d, mpp_sum , stddev(mpp_sum) over (partition by cust) as mpp_stdev , avg(mpp_sum) over (partition by cust) as mpp_mean , sum(mpp_sum) over (partition by cust) as glob_mpp_sum,  count(mpp_sum) over (partition by cust) as glob_mpp_count from  (select distinct cid as cust,  week(d) as week_d , sum(c) over (partition by cid, week(d)) as mpp_sum  from tc where year(d) = '2018') as inside where cust = 0 and week_d = 0;

+------+--------+-------------+------------+-------------+--------------+----------------+

| cust | week_d | mpp_sum     | mpp_stdev  | mpp_mean    | glob_mpp_sum | glob_mpp_count |

+------+--------+-------------+------------+-------------+--------------+----------------+

|    0 |      0 | 103715.8800 | 0.00000000 | 10.37158800 |      10.3716 |              1 |

+------+--------+-------------+------------+-------------+--------------+----------------+

1 row in set (0,052 sec)