MySQL对OR条件查询不支持优化，会进行全表扫描：
explain extended select * from like1 where name like 'abc%';
例如：
+----+-------------+-------+-------+---------------+-----------+---------+------+------+----------+-----------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-------+-------+---------------+-----------+---------+------+------+----------+-----------------------+
| 1 | SIMPLE | like1 | range | nameindex | nameindex | 23 | NULL | 1 | 100.00 | Using index condition |
+----+-------------+-------+-------+---------------+-----------+---------+------+------+----------+-----------------------+
1 row in set, 1 warning (0.00 sec)
explain extended select * from like1 where name like 'abc%' or name > 1;
+----+-------------+-------+------+---------------+------+---------+------+------+----------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-------+------+---------------+------+---------+------+------+----------+-------------+
| 1 | SIMPLE | like1 | ALL | nameindex | NULL | NULL | NULL | 1 | 100.00 | Using where |
+----+-------------+-------+------+---------------+------+---------+------+------+----------+-------------+
1 row in set, 2 warnings (0.01 sec)
大家还有那些对MySQL ， OR方面的优化可以讨论？
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