Hive-Hive函数

转移符号\
Function 函数
build-in 内置函数
show functions;
desc function upper;
desc formatted function upper;
desc extended function upper;
UDF User Defined Function 用户自定义函数

常用的时间函数

select * from dual;
select current_date from dual;
select current_timestamp from dual;
select unix_timestamp() from dual;
select unix_timestamp(‘2019-12-31 20:10:10’) from dual;
select unix_timestamp(‘20191231 20:10:10’,‘yyyyMMdd HH:mm:ss’) from dual;

desc extended function from_unixtime;
desc extended function to_date;
desc extended function year;
desc extended function month;
desc extended function day;
desc extended function hour;
desc extended function minute;
desc extended function second;

desc extended function date_add;
desc extended function date_sub;

类型转换函数

cast
binary 只能转string

数学函数

round
ceil ceiling
floor
abs
least
greatest

字符串处理

substr substring
concat
concat_ws
split (正则)
length

复杂类型处理

array_contains
sort_array
size
map_keys
map_values

json类型的数据的表

json_tuple
parse_url_tuple

isnull
isnotnull
assert_true
elt
nvl