SparkSQL操作Hive表数据

1. 启动Hadoop：./sbin/start-all.sh
2. 启动Spark-Shell：./bin/spark-shell --master local[2]

scala> spark.sql("show tables").show
+--------+---------+-----------+
|database|tableName|isTemporary|
+--------+---------+-----------+
| default|     dept|      false|
| default|      emp|      false|
+--------+---------+-----------+

scala> spark.sql("select * from emp").show
+-----+------+---------+----+----------+-------+------+------+
|empno| ename|      job| mgr|  hiredate|    sal|  comm|deptno|
+-----+------+---------+----+----------+-------+------+------+
| 7369| SMITH|    CLERK|7902|1980-12-17|  800.0|  null|    20|
| 7499| ALLEN| SALESMAN|7698| 1981-2-20| 1600.0| 300.0|    30|
| 7521|  WARD| SALESMAN|7698| 1981-2-22| 1250.0| 500.0|    30|
| 7566| JONES|  MANAGER|7839|  1981-4-2| 2975.0|  null|    20|
| 7654|MARTIN| SALESMAN|7698| 1981-9-28| 1250.0|1400.0|    30|
| 7698| BLAKE|  MANAGER|7839|  1981-5-1| 2850.0|  null|    30|
| 7782| CLARK|  MANAGER|7839|  1981-6-9| 2450.0|  null|    10|
| 7788| SCOTT|  ANALYST|7566| 1987-4-19| 3000.0|  null|    20|
| 7839|  KING|PRESIDENT|null|1981-11-17| 5000.0|  null|    10|
| 7844|TURNER| SALESMAN|7698|  1981-9-8| 1500.0|   0.0|    30|
| 7876| ADAMS|    CLERK|7788| 1987-5-23| 1100.0|  null|    20|
| 7900| JAMES|    CLERK|7698| 1981-12-3|  950.0|  null|    30|
| 7902|  FORD|  ANALYST|7566| 1981-12-3| 3000.0|  null|    20|
| 7934|MILLER|    CLERK|7782| 1982-1-23| 1300.0|  null|    10|
| 8888|  HIVE|  PROGRAM|7839| 1988-1-23|10300.0|  null|  null|
+-----+------+---------+----+----------+-------+------+------+




scala> spark.sql("select deptno,count(1) from emp group by deptno").show
+------+--------+
|deptno|count(1)|
+------+--------+
|  null|       1|
|    20|       5|
|    10|       3|
|    30|       6|
+------+--------+

scala> spark.sql("select deptno,count(1) from emp group by deptno").filter("deptno is not null").show
+------+--------+
|deptno|count(1)|
+------+--------+
|    20|       5|
|    10|       3|
|    30|       6|
+------+--------+

spark.sql("select deptno,count(1) from emp group by deptno").filter("deptno is not null").write.saveAsTable("hive_table")

org.apache.spark.sql.AnalysisException: Attribute name "count(1)" contains invalid character(s) among " ,;{}()\n\t=". Please use alias to rename it.;

scala> spark.sql("select deptno,count(1) as mount from emp group by deptno").filter("deptno is not null").write.saveAsTable("hive_table")
Warning: fs.defaultFS is not set when running "chgrp" command.                  
Warning: fs.defaultFS is not set when running "chmod" command.


scala> spark.sql("show tables")
res8: org.apache.spark.sql.DataFrame = [database: string, tableName: string ... 1 more field]


scala> spark.sql("show tables").show
+--------+----------+-----------+
|database| tableName|isTemporary|
+--------+----------+-----------+
| default|      dept|      false|
| default|       emp|      false|
| default|hive_table|      false|
+--------+----------+-----------+

scala> spark.sql("select * from hive_table").show
+------+-----+
|deptno|mount|
+------+-----+
|    20|    5|
|    10|    3|
|    30|    6|
+------+-----+




scala> spark.table("hive_table").show
+------+-----+
|deptno|mount|
+------+-----+
|    20|    5|
|    10|    3|
|    30|    6|
+------+-----+

spark.sqlContext.setConf("spark.sql.shuffle.partitions","10")


在生产环境中一定要注意设置spark.sql.shuffle.partitions，默认是200