Yu Chen created FLINK-35832:
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Summary: IFNULL returns error result in Flink SQL
Key: FLINK-35832
URL: https://issues.apache.org/jira/browse/FLINK-35832
Project: Flink
Issue Type: Bug
Components: Table SQL / Planner
Affects Versions: 2.0.0
Reporter: Yu Chen
Run following SQL in sql-client:
The correct result should be '16', but we got '1' on the master.
{code:java}
Flink SQL> SET 'sql-client.execution.result-mode' = 'tableau';
[INFO] Execute statement succeeded.
Flink SQL> select JSON_VALUE('{"a":16}','$.a'),
IFNULL(JSON_VALUE('{"a":16}','$.a'),'0');
+----+--------------------------------+--------------------------------+
| op | EXPR$0 | EXPR$1 |
+----+--------------------------------+--------------------------------+
| +I | 16 | 1 |
+----+--------------------------------+--------------------------------+
Received a total of 1 row (0.30 seconds){code}
With some quick debugging, I guess it may be caused by
[FLINK-24413|https://issues.apache.org/jira/browse/FLINK-24413] which was
introduced in Flink version 1.15.
I think the wrong result '1' was produced because the simplifying SQL procedure
assumed that parameter 1 and parameter 2 ('0' was char) of IFNULL were of the
same type, and therefore implicitly cast '16' to char, resulting in the
incorrect result.
I have tested the SQL in the following version:
||Flink Version||Result||
|1.13|16,16|
|1.17|16,1|
|1.19|16,1|
|master|16,1|
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