Test Case Setup     create table n1 (id STRING) stored as parquet; insert into n1 values ('-1234'); insert into n1 values ('7890');     Results impalad version 2.12.0-cdh5.15.2     SELECT `id` , CAST(`id` AS DECIMAL(38,0)) / 20 * 20 AS D0 , CAST(`id` AS DECIMAL(38,0)) / 20.0 * 20 AS D1 FROM n1 ORDER BY `id`; +----------+-------+---------+ | id | d0 | d1 | +----------+-------+---------+ | -1234 | -1220 | -1234.0 | | 7890 | 7880 | 7890.0 | +----------+-------+---------+ Fetched 4 row(s) in 0.56s     When we are casting the "id" column to a decimal without scale and dividing by an integer, even though the answer should have a scale (-1234 / 20 = -61.7) we lose the scale and the result is truncated to -61. This is then multiplied by 20 to give -1220 which is column d0. This does not get us back to the same value that we started with which was -1234.   When we divide by a decimal value (20.0) the result of -61.7 is preserved, which gets us back to the correct value of the "id" in column d1.   impalad version 3.2.0-cdh6.2.0   SELECT `id` , CAST(`id` AS DECIMAL(38,0)) / 20 * 20 AS D0 , CAST(`id` AS DECIMAL(38,0)) / 20.0 * 20 AS D1 FROM n1 ORDER BY `id`; +-------+--------------+--------------+ | id | d0 | d1 | +-------+--------------+--------------+ | -1234 | -1234.000000 | -1234.000000 | | 7890 | 7890.000000 | 7890.000000 | +-------+--------------+--------------+   Notice the change in behaviour with this later version of Impala.   This looks to me like a bug that has been fixed.   Could you please confirm and point me to the IMPALA Jira that explains this bug?   ... View more