drop table if exists t0,t1,t2,t3;
create table t0 (a int);
INSERT INTO t0 VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
# r_filtered=30%, because 3 rows match: 0,1,2
analyze format=json select * from t0 where a<3;
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "t0",
      "access_type": "ALL",
      "r_loops": 1,
      "rows": 10,
      "r_rows": 10,
      "filtered": 100,
      "r_filtered": 30,
      "attached_condition": "(t0.a < 3)"
    }
  }
}
create table t1 (a int, b int, c int, key(a));
insert into t1 select A.a*10 + B.a, A.a*10 + B.a, A.a*10 + B.a from t0 A, t0 B;
analyze
select * from t0, t1 where t1.a=t0.a and t0.a > 9;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	10	100.00	0.00	Using where
1	SIMPLE	t1	ref	a	a	5	test.t0.a	1	NULL	100.00	NULL	
analyze format=json 
select * from t0, t1 where t1.a=t0.a and t0.a > 9;
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "t0",
      "access_type": "ALL",
      "r_loops": 1,
      "rows": 10,
      "r_rows": 10,
      "filtered": 100,
      "r_filtered": 0,
      "attached_condition": "((t0.a > 9) and (t0.a is not null))"
    },
    "table": {
      "table_name": "t1",
      "access_type": "ref",
      "possible_keys": ["a"],
      "key": "a",
      "key_length": "5",
      "used_key_parts": ["a"],
      "ref": ["test.t0.a"],
      "r_loops": 0,
      "rows": 1,
      "r_rows": null,
      "filtered": 100,
      "r_filtered": null
    }
  }
}
analyze
select * from t0, t1 where t1.a=t0.a and t1.b<4;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	10	100.00	100.00	Using where
1	SIMPLE	t1	ref	a	a	5	test.t0.a	1	1	100.00	40.00	Using where
analyze format=json
select * from t0, t1 where t1.a=t0.a and t1.b<4;
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "t0",
      "access_type": "ALL",
      "r_loops": 1,
      "rows": 10,
      "r_rows": 10,
      "filtered": 100,
      "r_filtered": 100,
      "attached_condition": "(t0.a is not null)"
    },
    "table": {
      "table_name": "t1",
      "access_type": "ref",
      "possible_keys": ["a"],
      "key": "a",
      "key_length": "5",
      "used_key_parts": ["a"],
      "ref": ["test.t0.a"],
      "r_loops": 10,
      "rows": 1,
      "r_rows": 1,
      "filtered": 100,
      "r_filtered": 40,
      "attached_condition": "(t1.b < 4)"
    }
  }
}
analyze 
select * from t1 tbl1, t1 tbl2 where tbl1.b<2 and tbl2.b>5;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
1	SIMPLE	tbl1	ALL	NULL	NULL	NULL	NULL	100	100	100.00	2.00	Using where
1	SIMPLE	tbl2	ALL	NULL	NULL	NULL	NULL	100	100	100.00	94.00	Using where; Using join buffer (flat, BNL join)
analyze format=json
select * from t1 tbl1, t1 tbl2 where tbl1.b<20 and tbl2.b<60;
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "tbl1",
      "access_type": "ALL",
      "r_loops": 1,
      "rows": 100,
      "r_rows": 100,
      "filtered": 100,
      "r_filtered": 20,
      "attached_condition": "(tbl1.b < 20)"
    },
    "block-nl-join": {
      "table": {
        "table_name": "tbl2",
        "access_type": "ALL",
        "r_loops": 1,
        "rows": 100,
        "r_rows": 100,
        "filtered": 100,
        "r_filtered": 60,
        "attached_condition": "(tbl2.b < 60)"
      },
      "buffer_type": "flat",
      "join_type": "BNL",
      "r_filtered": 100
    }
  }
}
analyze format=json
select * from t1 tbl1, t1 tbl2 where tbl1.b<20 and tbl2.b<60 and tbl1.c > tbl2.c;
EXPLAIN
{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "tbl1",
      "access_type": "ALL",
      "r_loops": 1,
      "rows": 100,
      "r_rows": 100,
      "filtered": 100,
      "r_filtered": 20,
      "attached_condition": "(tbl1.b < 20)"
    },
    "block-nl-join": {
      "table": {
        "table_name": "tbl2",
        "access_type": "ALL",
        "r_loops": 1,
        "rows": 100,
        "r_rows": 100,
        "filtered": 100,
        "r_filtered": 60,
        "attached_condition": "(tbl2.b < 60)"
      },
      "buffer_type": "flat",
      "join_type": "BNL",
      "attached_condition": "(tbl1.c > tbl2.c)",
      "r_filtered": 15.833
    }
  }
}
drop table t1;
drop table t0;