hive 函数

🧙 Questions

hive在DML中常用的函数

☄️ Ideas

创建dual表

create table dual (dummy string);
insert into dual values ('1 x 1');

空判断

-- isnull(val) --> boolean
select isnull(NULL) from dual;
-- result: true

非空判断

-- isnotnull(val) --> boolean
select isnotnull(NULL) from dual;
-- result: false

正则表达式替换

-- regexp_replace('INITIAL_STRING','PATTERN','REPLACEMENT') --> string
select regexp_replace(dummy,'x','y') from dual; 
-- result: 1 y 1

字符串切割

-- substring('A', int start, int len) --> string
select substring(dummy,0,2) from dual;
-- result: 1

条件函数

select
  (case
    when dummy = 'x'  then 5
    when (dummy = '1 x 1') then 6 
  end) 
from dual;
-- result: 6

🔗 Links

• hive docs
• hive function website