set
@tmp_switch_sarg_casefold=@@optimizer_switch,
optimizer_switch='sargable_casefold=on';
create table t1 (
s1 varchar(15) collate utf8mb3_bin,
s2 varchar(15) collate utf8mb3_general_ci
) partition by key (s2) partitions 4;
insert into t1 values ('aa','aa'),('bb','bb');
explain format=json select * from t1 where upper(s2)='AA';
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "t1",
          "partitions": ["p2"],
          "access_type": "system",
          "rows": 1,
          "filtered": 100
        }
      }
    ]
  }
}
explain format=json delete from t1 where upper(s2)='AA';
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "table": {
      "delete": 1,
      "table_name": "t1",
      "partitions": ["p2"],
      "access_type": "ALL",
      "rows": 1,
      "attached_condition": "t1.s2 = 'AA'"
    }
  }
}
explain format=json update t1 set s1='aaa' where upper(s2)='AA';
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "table": {
      "update": 1,
      "table_name": "t1",
      "partitions": ["p2"],
      "access_type": "ALL",
      "rows": 1,
      "attached_condition": "t1.s2 = 'AA'"
    }
  }
}
drop table t1;
set optimizer_switch=@tmp_switch_sarg_casefold;