我的hql语句是：select a.s_id,a.s_name,count(b.c_id),sum(b.s_score) from student a join score b on a.s_id = b.s_id group by a.s_id,a.s_name;
以下是程序执行过程中的代码：
WARNING: Hive-on-MR is deprecated in Hive 2 and may not be available in the future versions. Consider using a different execution engine (i.e. spark, tez) or using Hive 1.X releases.
Query ID = hadoop00_20190707222645_088edcae-7934-42ab-be0d-162c6c3175ed
Total jobs = 1
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/hadoop00/apps/apache-hive-2.3.4-bin/lib/log4j-slf4j-impl-2.6.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/hadoop00/hadoop-2.7.7/share/hadoop/common/lib/slf4j-log4j12-1.7.10.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.apache.logging.slf4j.Log4jLoggerFactory]
2019-07-07 22:27:08 Starting to launch local task to process map join; maximum memory = 518979584
2019-07-07 22:27:13 Dump the side-table for tag: 1 with group count: 7 into file: file:/tmp/hadoop00/13449221-f642-4dc7-a09d-61592e221ee3/hive_2019-07-07_22-26-45_439_2116768033594646754-1/-local-10005/HashTable-Stage-2/MapJoin-mapfile01--.hashtable
2019-07-07 22:27:13 Uploaded 1 File to: file:/tmp/hadoop00/13449221-f642-4dc7-a09d-61592e221ee3/hive_2019-07-07_22-26-45_439_2116768033594646754-1/-local-10005/HashTable-Stage-2/MapJoin-mapfile01--.hashtable (537 bytes)
2019-07-07 22:27:13 End of local task; Time Taken: 4.37 sec.
Execution completed successfully
MapredLocal task succeeded
Launching Job 1 out of 1
Number of reduce tasks not specified. Estimated from input data size: 1
In order to change the average load for a reducer (in bytes):
set hive.exec.reducers.bytes.per.reducer=
In order to limit the maximum number of reducers:
set hive.exec.reducers.max=
In order to set a constant number of reducers:
set mapreduce.job.reduces=
Starting Job = job_1562492270355_0001, Tracking URL = http://hadoop03:8088/proxy/application_1562492270355_0001/
Kill Command = /home/hadoop00/hadoop-2.7.7/bin/hadoop job -kill job_1562492270355_0001
Hadoop job information for Stage-2: number of mappers: 1; number of reducers: 1
2019-07-07 22:29:22,969 Stage-2 map = 0%, reduce = 0%
2019-07-07 22:30:23,579 Stage-2 map = 0%, reduce = 0%
2019-07-07 22:31:24,667 Stage-2 map = 0%, reduce = 0%
2019-07-07 22:32:21,811 Stage-2 map = 100%, reduce = 0%, Cumulative CPU 26.68 sec
2019-07-07 22:33:17,853 Stage-2 map = 100%, reduce = 67%, Cumulative CPU 30.33 sec
2019-07-07 22:33:50,432 Stage-2 map = 100%, reduce = 100%, Cumulative CPU 52.09 sec
MapReduce Total cumulative CPU time: 52 seconds 90 msec
Ended Job = job_1562492270355_0001
MapReduce Jobs Launched:
Stage-Stage-2: Map: 1 Reduce: 1 Cumulative CPU: 52.09 sec HDFS Read: 12916 HDFS Write: 87 SUCCESS
Total MapReduce CPU Time Spent: 52 seconds 90 msec
OK
Time taken: 430.739 seconds
两个表如下：
student：
s_id s_name s_brith s_sex
01 赵雷 1990-01-01 男 NULL NULL NULL
02 钱电 1990-12-21 男 NULL NULL NULL
03 孙风 1990-05-20 男 NULL NULL NULL
04 李云 1990-08-06 男 NULL NULL NULL
05 周梅 1991-12-01 女 NULL NULL NULL
06 吴兰 1992-03-01 女 NULL NULL NULL
07 郑竹 1989-07-01 女 NULL NULL NULL
08 王菊 1990-01-20 女 NULL NULL NULL
score:
s_id c_id s_score
01 01 80
01 02 90
01 03 99
02 01 70
02 02 60
02 03 80
03 01 80
03 02 80
03 03 80
04 01 50
04 02 30
04 03 20
05 01 76
05 02 87
06 01 31
06 03 34
07 02 89
07 03 98