9.10 执行计划（Explain）

1．基本语法 EXPLAIN [EXTENDED | DEPENDENCY | AUTHORIZATION] query 2．案例实操 （1）查看下面这条语句的执行计划

hive (default)> explain select * from emp;
hive (default)> explain select deptno, avg(sal) avg_sal from emp group by deptno;

（2）查看详细执行计划

hive (default)> explain extended select * from emp;
hive (default)> explain extended select deptno, avg(sal) avg_sal from emp group by deptno;