[MDEV-20285] Wrong result on INSERT..SELECT when converting from SIGNED to UNSIGNED Created: 2019-08-08  Updated: 2019-08-08  Resolved: 2019-08-08

Status: Closed
Project: MariaDB Server
Component/s: Data types
Affects Version/s: 5.5, 10.0, 10.1, 10.2, 10.3, 10.4
Fix Version/s: 10.3.18, 10.4.8

Type: Bug Priority: Major
Reporter: Alexander Barkov Assignee: Alexander Barkov
Resolution: Fixed Votes: 0
Labels: None


 Description    

CREATE OR REPLACE TABLE t1 (a TINYINT UNSIGNED);
 
CREATE OR REPLACE TABLE t2 (a TINYINT);
 
INSERT INTO t1 VALUES (255);
 
INSERT IGNORE INTO t2 SELECT a FROM t1;
 
SELECT * FROM t2;


+------+
 
| a    |
 
+------+
 
|   -1 |
 
+------+

Notice, an out of range unsigned value of 255 was silently converted to its negative complement.

The expected result is 127 with a warning.
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