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|
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;
|
