hive array、map、struct使用

hive提供了复合数据类型:
Structs: structs内部的数据可以通过DOT(.)来存取,例如,表中一列c的类型为STRUCT{a INT; b INT},我们可以通过c.a来访问域a
Maps(K-V对):访问指定域可以通过[“指定域名称”]进行,例如,一个Map M包含了一个group-》gid的kv对,gid的值可以通过M[‘group’]来获取
Arrays:array中的数据为相同类型,例如,假如array A中元素[‘a’,’b’,’c’],则A[1]的值为’b’

Struct使用
建表:

create table student_test(id INT, info struct<name:STRING, age:INT>) 
ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' 
COLLECTION ITEMS TERMINATED BY ':';
OK
Time taken: 0.446 seconds
'FIELDS TERMINATED BY' :字段与字段之间的分隔符
''COLLECTION ITEMS TERMINATED BY' :一个字段各个item的分隔符

导入数据:

$ cat test5.txt
1,zhou:30
2,yan:30
3,chen:20
4,li:80
hive> LOAD DATA LOCAL INPATH '/home/work/data/test5.txt' INTO TABLE student_test;
Copying data from file:/home/work/data/test5.txt
Copying file: file:/home/work/data/test5.txt
Loading data to table default.student_test
OK
Time taken: 0.35 seconds

查询:

hive> select info.age from student_test;
Total MapReduce jobs = 1
......
Total MapReduce CPU Time Spent: 490 msec
OK
30
30
20
80
Time taken: 21.677 seconds

Array使用
建表:

create table class_test(name string, student_id_list array<INT>) 
ROW FORMAT DELIMITED 
FIELDS TERMINATED BY ',' 
COLLECTION ITEMS TERMINATED BY ':';
OK
Time taken: 0.099 seconds

导入数据:

$ cat test6.txt
034,1:2:3:4
035,5:6
036,7:8:9:10
hive> LOAD DATA LOCAL INPATH '/home/work/data/test6.txt' INTO TABLE class_test ;
Copying data from file:/home/work/data/test6.txt
Copying file: file:/home/work/data/test6.txt
Loading data to table default.class_test
OK
Time taken: 0.198 seconds

查询:

hive> select student_id_list[3] from class_test;
Total MapReduce jobs = 1
......
Total MapReduce CPU Time Spent: 480 msec
OK
4
NULL
10
Time taken: 21.574 seconds

Map使用
建表:

create table employee(id string, perf map<string, int>) 
ROW FORMAT DELIMITED 
FIELDS TERMINATED BY '\t' 
COLLECTION ITEMS TERMINATED BY ',' 
MAP KEYS TERMINATED BY ':'; 
OK
Time taken: 0.144 seconds
‘MAP KEYS TERMINATED BY’ :key value分隔符

导入数据:

$ cat test7.txt
1 job:80,team:60,person:70
2 job:60,team:80
3 job:90,team:70,person:100
hive> LOAD DATA LOCAL INPATH '/home/work/data/test7.txt' INTO TABLE employee;

查询:

hive> select perf['person'] from employee;
Total MapReduce jobs = 1
......
Total MapReduce CPU Time Spent: 460 msec
OK
70
NULL
100
Time taken: 20.902 seconds
hive> select perf['person'] from employee where perf['person'] is not null;
Total MapReduce jobs = 1
.......
Total MapReduce CPU Time Spent: 610 msec
OK
70
100
Time taken: 21.989 seconds
hive>

1 thought on “hive array、map、struct使用

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