摘要：
http://stackoverflow.com/questions/10953143/join-performance-oracle-vs-mysql翻译自上面的链接。Given a query reduced to the form:select b.field1from table_a a innerjoin table_b b on b.field1 = a.field1 leftjoin table_c c on c.field1 = a.field1 leftjoin table_d d on d.field1 = b.field1 leftjoin tab... 阅读全文