json_unquote and like operator has different behavior after pushing down to TiKV

[YangKeao]

Enhancement

create table t (i INT, j JSON);
insert into t values(3, cast(X'ABCD' as JSON));
select i from t where json_unquote(j) like 'base64:type253:q80=';

It returns empty with tikv store, but in MySQL (base64:type16:q80=) and TiDB unistore, it gives 3

[xiongjiwei]

mysql root@localhost:test> select json_unquote(cast(X'ABCD' as JSON)) like 'base64:type253:q80=';
+----------------------------------------------------------------+
| json_unquote(cast(X'ABCD' as JSON)) like 'base64:type253:q80=' |
+----------------------------------------------------------------+
| 0                                                              |
+----------------------------------------------------------------+

[YangKeao]

mysql root@localhost:test> select json_unquote(cast(X'ABCD' as JSON)) like 'base64:type253:q80=';
+----------------------------------------------------------------+
| json_unquote(cast(X'ABCD' as JSON)) like 'base64:type253:q80=' |
+----------------------------------------------------------------+
| 0                                                              |
+----------------------------------------------------------------+

It's because the projection is not pushed down?

[xiongjiwei]

it is mysql8.0 result

[YangKeao]

it is mysql8.0 result

Use base64:type16:q80= for MySQL? As the type code has a little difference

[xiongjiwei]

I see