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explain select * from t1,t2,t3 where t2.key1 = t1.col1 and t3.key1<40;
+----+-------------+-------+-------+---------------+------+---------+--------------+------+--------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+-------+---------------+------+---------+--------------+------+--------------------------------+
| 1 | SIMPLE | t1 | ALL | NULL | NULL | NULL | NULL | 10 | |
| 1 | SIMPLE | t2 | ref | key1 | key1 | 5 | test.t1.col1 | 2 | Using where |
| 1 | SIMPLE | t3 | range | key1 | key1 | 5 | NULL | 40 | Using where; Using join buffer |
+----+-------------+-------+-------+---------------+------+---------+--------------+------+--------------------------------+
|
