unexpect invalid json text error when query with json_extract

[Deardrops]

Description

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?
   If possible, provide a recipe for reproducing the error.

create table t1(f1 json);
insert into t1(f1) values ('"asd"'),('"asdf"'),('"asasas"');
select f1 from t1 where json_extract(f1,"$") in ("asd","asasas","asdf");

2. What did you expect to see?

3. What did you see instead?

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

SIG slack channel

#sig-exec

Score

• 300

Mentor

• @XuHuaiyu

[wjhuang2016]

https://dev.mysql.com/doc/refman/8.0/en/json.html#json-comparison
The problem is that TiDB supports json comparison in in claue while MySQL doesn't.

[wjhuang2016]

MySQL support json comparison in in clause now, in 8.0.18

[ghost]

I have to say, the MySQL handling of just throwing a warning here is very unsafe. It should be an error (as it is in TiDB). Having said that, this works as expected in MySQL 8.0. Here is a testcase showing the behavior of MySQL 5.7/8.0 and TiDB:

DROP TABLE IF EXISTS t1;
create table t1(f1 json);
insert into t1(f1) values ('"asd"'),('"asdf"'),('"asasas"');
select f1 from t1 where json_extract(f1,"$") in ("asd","asasas","asdf");

..

mysql [localhost:5731] {root} (test) > select f1 from t1 where json_extract(f1,"$") in ("asd","asasas","asdf");
Empty set, 1 warning (0.00 sec)

mysql [localhost:5731] {root} (test) > show warnings;
+---------+------+-----------------------------------------------------------------------------------+
| Level   | Code | Message                                                                           |
+---------+------+-----------------------------------------------------------------------------------+
| Warning | 1235 | This version of MySQL doesn't yet support 'comparison of JSON in the IN operator' |
+---------+------+-----------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql [localhost:8021] {msandbox} (test) > select f1 from t1 where json_extract(f1,"$") in ("asd","asasas","asdf");
+----------+
| f1       |
+----------+
| "asd"    |
| "asdf"   |
| "asasas" |
+----------+
3 rows in set (0.00 sec)

mysql> select f1 from t1 where json_extract(f1,"$") in ("asd","asasas","asdf");
ERROR 1105 (HY000): invalid data type: Illegal Json text: Error("expected value", line: 1, column: 1)
mysql> select tidb_version()\G
*************************** 1. row ***************************
tidb_version(): Release Version: v4.0.0-beta.2-807-g824df7675
Edition: Community
Git Commit Hash: 824df767559b8544af0cb71509135d322de1cd47
Git Branch: master
UTC Build Time: 2020-07-20 04:47:45
GoVersion: go1.13
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false
1 row in set (0.00 sec)

[ti-srebot]

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