November 2021
Intermediate to advanced
340 pages
10h 46m
Chinese
Content preview from Spark快速大数据分析（第2版）
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Spark SQL
与
DataFrame
：
读写外部数据源
｜
107
Time taken: 0.637 seconds
spark-sql>
3.
运行
Spark SQL
查询
现在表中有了数据，可以对它运行
Spark SQL
查询。先看看我们的元数据库有哪些表。
spark-sql>
SHOW TABLES;
default people false
Time taken: 0.016 seconds, Fetched 1 row(s)
下一步是找出表中有多少人年龄小于
20
岁。
spark-sql>
SELECT * FROM people WHERE age < 20;
Samantha 19
Time taken: 0.593 seconds, Fetched 1 row(s)
再看看哪些人没有年龄数据。
spark-sql>
SELECT name FROM people WHERE age IS NULL;
Michael
Time taken: 0.272 seconds, Fetched 1 row(s)
5.2.2
使用
Beeline
如果使用过
Hive
，那么你应该熟悉
Hive
附带的命令行工具
Beeline
，它是在
HiveServer2
上运行
HiveQL
查询的一个常用工具
。
Beeline
是基于
SQLLine
命令行接口实现的
JDBC
客户端。你也可以用它在
Spark
Thrift
服务器上执行
Spark SQL
查询。注意，当前实现的
Thrift JDBC/ODBC
服务器对应的是
Hive 1.2.1 ...
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