| Bug #79292 | cast('-123.9' as signed) returns -123, not expected -124 | ||
|---|---|---|---|
| Submitted: | 16 Nov 2015 9:48 | Modified: | 19 Nov 2015 21:56 |
| Reporter: | Su Dylan | Email Updates: | |
| Status: | Verified | Impact on me: | |
| Category: | MySQL Server: DML | Severity: | S3 (Non-critical) |
| Version: | 5.0/5.1/5.5/5.6/5.7 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[16 Nov 2015 10:27]
Peter Laursen
All (recent, at least) MySQL (and alos MariaDB) versions seem affected - for instance
SELECT VERSION(); -- 5.6.14-LOG
SELECT CAST('-123.9' AS SIGNED); -- returns -123
SELECT CAST(-123.9 AS SIGNED); -- returns -124
[19 Nov 2015 21:56]
MySQL Verification Team
Thank you for the bug report. Same behavior since 5.0.
C:\dbs>c:\dbs\5.7\bin\mysql -uroot -p --port=3570 --prompt="mysql 5.7 > "
Enter password: ******
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 5.7.10 Source distribution PULL: 2015-NOV-07
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owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql 5.7 > use test
Database changed
mysql 5.7 > drop table if exists t1;
Query OK, 0 rows affected (0.07 sec)
mysql 5.7 > create table t1(c1 int);
Query OK, 0 rows affected (0.03 sec)
mysql 5.7 > insert into t1 values('-123.9');
Query OK, 1 row affected (0.04 sec)
mysql 5.7 > select c1, cast('-123.9' as signed) from t1;
+------+--------------------------+
| c1 | cast('-123.9' as signed) |
+------+--------------------------+
| -124 | -123 |
+------+--------------------------+
1 row in set, 1 warning (0.17 sec)
Description: Output: ======= mysql> drop table if exists t1; Query OK, 0 rows affected (0.01 sec) mysql> create table t1(c1 int); insert into t1 values('-123.9'); Query OK, 0 rows affected (0.01 sec) mysql> insert into t1 values('-123.9'); Query OK, 1 row affected (0.00 sec) mysql> select c1, cast('-123.9' as signed) from t1; +------+--------------------------+ | c1 | cast('-123.9' as signed) | +------+--------------------------+ | -124 | -123 | +------+--------------------------+ 1 row in set, 1 warning (0.00 sec) mysql> mysql> mysql> select version(); +-----------+ | version() | +-----------+ | 5.7.8-rc | +-----------+ 1 row in set (0.00 sec) Problem: ======== In this example, in select list, c1 and "cast('-123.9' as signed)" are expected to return consistent result -124. How to repeat: drop table if exists t1; create table t1(c1 int); insert into t1 values('-123.9'); select c1, cast('-123.9' as signed) from t1; Suggested fix: In this example, in select list, c1 and "cast('-123.9' as signed)" are expected to return consistent result -124.