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Type:
Bug
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Status: Open (View Workflow)
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Priority:
Major
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Resolution: Unresolved
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Affects Version/s: 5.5, 10.1, 10.2, 10.3, 10.4, 10.0
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Fix Version/s: 10.4
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Component/s: Data types
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Labels:None
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Epic Link:
I run this script:
DROP TABLE IF EXISTS t1,t2,t3; |
CREATE TABLE t1 (a CHAR(1), b CHAR(2)); |
CREATE TABLE t2 AS SELECT COALESCE(a,b) AS c FROM t1; |
CREATE TABLE t3 AS SELECT a FROM t1 UNION SELECT b FROM t1; |
DESC t2; |
DESC t3; |
It produces these two result sets:
+-------+------------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
|
+-------+------------+------+-----+---------+-------+
|
| c | varchar(2) | YES | | NULL | |
|
+-------+------------+------+-----+---------+-------+
|
+-------+---------+------+-----+---------+-------+
|
| Field | Type | Null | Key | Default | Extra |
|
+-------+---------+------+-----+---------+-------+
|
| a | char(2) | YES | | NULL | |
|
+-------+---------+------+-----+---------+-------+
|
Notice:
- CHAR + CHAR gives VARCHAR in COALESCE
- CHAR + CHAR gives CHAR in UNION
The latter looks more correct.
Hybrid functions should be fixed to preserve the data type.