[I] `decimal % 1` returns 0 for non-nullable decimal columns [datafusion]

["neilconway (via GitHub)" <gi...@apache.org>]

neilconway opened a new issue, #25946:
URL: https://github.com/apache/datafusion/issues/25946

   ### Describe the bug
   
   For a decimal column declared `NOT NULL`, `col % 1` returns 0 for every row: `1.50 % 1` returns `0.00`. The same expression on a nullable decimal column returns the correct `0.50`. Filters on the expression are wrong as well.
   
   ### To Reproduce
   
   ```sql
   CREATE TABLE t (d DECIMAL(10,2) NOT NULL, n DECIMAL(10,2)) AS VALUES (1.50, 1.50);
   
   SELECT d % 1 AS not_null_col, n % 1 AS nullable_col FROM t;
   -- not_null_col: 0.00 (wrong), nullable_col: 0.50
   
   SELECT count(*) AS cnt FROM t WHERE d % 1 = 0;
   -- 1 (expected 0)
   
   SELECT d % CAST(1 AS DECIMAL(10,2)) AS dec_literal FROM t;
   -- 0.00 (wrong)
   ```
   
   ### Expected behavior
   
   `d % 1` returns `0.50`, matching the nullable column, and the `WHERE` query returns 0.
   
   ### Additional context
   
   Reproduced on `main` at commit 2b1fcae86, in both release and debug builds.
   
   *This bug report was generated by Claude.*
   


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Re: [I] `decimal % 1` returns 0 for non-nullable decimal columns [datafusion]

["2010YOUY01 (via GitHub)" <gi...@apache.org>]

2010YOUY01 closed issue #25946: `decimal % 1` returns 0 for non-nullable decimal columns
URL: https://github.com/apache/datafusion/issues/25946


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