mysql> create index ind_t2_name on t2(name);
Query OK, 0 rows affected (0.18 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> create index ind_t2_addr on t2(address);
Query OK, 0 rows affected (0.11 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> explain select * from t2 where name='name44' or address='address888';
+----+-------------+-------+------------+-------------+-------------------------+-------------------------+---------+------+------+----------+---------------------------------------------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-------+------------+-------------+-------------------------+-------------------------+---------+------+------+----------+---------------------------------------------------+
| 1 | SIMPLE | t2 | NULL | index_merge | ind_t2_name,ind_t2_addr | ind_t2_name,ind_t2_addr | 63,153 | NULL | 2 | 100.00 | Using union(ind_t2_name,ind_t2_addr); Using where |
+----+-------------+-------+------------+-------------+-------------------------+-------------------------+---------+------+------+----------+---------------------------------------------------+
1 row in set, 1 warning (0.53 sec)
在mysql5.5或以前的版本单表只能使用一条索引，不能对2条索引进行合并，最好还是把or修改成union all
select * from t2 where name='name44’ union all select * from t2 where address='address888';
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/28572479/viewspace-2137876/ ，如需转载，请注明出处，否则将追究法律责任。
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