hive函式總結---表生成函式
阿新 • • 發佈:2018-12-18
explode將hive的複雜資料型別拆分成多行。
explode (array)
select explode(array('A','B','C'));
select explode(array('A','B','C')) as col;
select tf.* from (select 0) t lateral view explode(array('A','B','C')) tf;
select tf.* from (select 0) t lateral view explode(array('A','B','C')) tf as col;
結果
explode (map)
select explode(map('A',10,'B',20,'C',30)); select explode(map('A',10,'B',20,'C',30)) as (key,value); select tf.* from (select 0) t lateral view explode(map('A',10,'B',20,'C',30)) tf; select tf.* from (select 0) t lateral view explode(map('A',10,'B',20,'C',30)) tf as key,value; 結果
posexplode (array)
select posexplode(array('A','B','C'));
select posexplode(array('A','B','C')) as (pos,val);
select tf.* from (select 0) t lateral view posexplode(array('A','B','C')) tf;
select tf.* from (select 0) t lateral view posexplode(array('A','B','C')) tf as pos,val;
結果
inline (array of structs)
select inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02'))); select inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02'))) as (col1,col2,col3); select tf.* from (select 0) t lateral view inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02'))) tf; select tf.* from (select 0) t lateral view inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02'))) tf as col1,col2,col3; 結果
stack (values)
select stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01');
select stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01') as (col0,col1,col2);
select tf.* from (select 0) t lateral view stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01') tf;
select tf.* from (select 0) t lateral view stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01') tf as col0,col1,col2;
結果