嵌套循环(NESTED LOOPS)HASH 连接(HASH JOIN)HASH JOIN 原理介绍排序合并连接(SORT MERGE JOIN)笛卡儿连接(CARTESIAN JOIN)标量子查询(SCALAR SUBQUERY)半连接(SEMI JOIN)反连接(ANTI JOIN)FILTERIN 与 EXISTS 谁快谁慢SQL 语句的本质