行转列：多行转多列
行转列：多行转单列
--2、多行转单列
select * from row2col1;
select concat("it","cast","And","heima");
select concat("it","cast","And",null);
select concat_ws("-","itcast","And","heima");
select concat_ws("-","itcast","And",null);
select collect_list(col1) from row2col1;
select collect_set(col1) from row2col1;
--建表
create table row2col2(
col1 string,
col2 string,
col3 int
)row format delimited fields terminated by '\t';
--加载数据到表中
load data local inpath '/root/hivedata/r2c2.txt' into table row2col2;
select * from row2col2;
describe function extended concat_ws;
--最终SQL实现
select
col1,
col2,
concat_ws(',', collect_list(cast(col3 as string))) as col3
from
row2col2
group by
col1, col2;列转行：多列转多行
列转行：单列转多行
#完整的sql
--------------------------------hive行列转换-------------------------------------------------------
--1、多行转多列
--case when 语法1
select
id,
case
when id < 2 then 'a'
when id = 2 then 'b'
else 'c'
end as caseName
from tb_url;
--case when 语法2
select
id,
case id
when 1 then 'a'
when 2 then 'b'
else 'c'
end as caseName
from tb_url;
--建表
create table row2col1(
col1 string,
col2 string,
col3 int
) row format delimited fields terminated by '\t';
--加载数据到表中
load data local inpath '/root/hivedata/r2c1.txt' into table row2col1;
select *
from row2col1;
--sql最终实现
select
col1 as col1,
max(case col2 when 'c' then col3 else 0 end) as c,
max(case col2 when 'd' then col3 else 0 end) as d,
max(case col2 when 'e' then col3 else 0 end) as e
from
row2col1
group by
col1;
--2、多行转单列
select * from row2col1;
select concat("it","cast","And","heima");
select concat("it","cast","And",null);
select concat_ws("-","itcast","And","heima");
select concat_ws("-","itcast","And",null);
select collect_list(col1) from row2col1;
select collect_set(col1) from row2col1;
--建表
create table row2col2(
col1 string,
col2 string,
col3 int
)row format delimited fields terminated by '\t';
--加载数据到表中
load data local inpath '/root/hivedata/r2c2.txt' into table row2col2;
select * from row2col2;
describe function extended concat_ws;
--最终SQL实现
select
col1,
col2,
concat_ws(',', collect_list(cast(col3 as string))) as col3
from
row2col2
group by
col1, col2;
--3、多列转多行
select 'b','a','c'
union
select 'a','b','c'
union
select 'a','b','c';
--创建表
create table col2row1
(
col1 string,
col2 int,
col3 int,
col4 int
) row format delimited fields terminated by '\t';
--加载数据
load data local inpath '/root/hivedata/c2r1.txt' into table col2row1;
select *
from col2row1;
--最终实现
select col1, 'c' as col2, col2 as col3 from col2row1
UNION ALL
select col1, 'd' as col2, col3 as col3 from col2row1
UNION ALL
select col1, 'e' as col2, col4 as col3 from col2row1;
--4、单列转多行
select explode(split("a,b,c,d",","));
--创建表
create table col2row2(
col1 string,
col2 string,
col3 string
)row format delimited fields terminated by '\t';
--加载数据
load data local inpath '/root/hivedata/c2r2.txt' into table col2row2;
select * from col2row2;
select explode(split(col3,',')) from col2row2;
--SQL最终实现
select
col1,
col2,
lv.col3 as col3
from
col2row2
lateral view
explode(split(col3, ',')) lv as col3;
