Error:
Unable to open underlying table which is differently defined or of non-MyISAM type or doesn’t exist
Reason:
- MERGE引擎仅适用于MYISAM表
- union了不存在的表
- MERGE的时候引用了不在同一个数据库中的表,并且该表没有指定数据库名字
- 各个表的结构(索引、引擎、列、字符集等)不完全一致
Unable to open underlying table which is differently defined or of non-MyISAM type or doesn’t exist