Hive 内置函数

内置函数

内容较多，见《Hive官方文档》

https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF

1）查看系统自带的函数

hive> show functions;

hive (default)> show functions;
OK
tab_name
!
!=
%
&
*
+
-
/
<
<=
<=>
<>
=
==
>
>=
^
abs
acos
add_months
and
array
array_contains
ascii
asin
assert_true
atan
avg
base64
between
bin
case
cbrt
ceil
ceiling
coalesce
collect_list
collect_set
compute_stats
concat
concat_ws
context_ngrams
conv
corr
cos
count
covar_pop
covar_samp
crc32
create_union
cume_dist
current_database
current_date
current_timestamp
current_user
date_add
date_format
date_sub
datediff
day
dayofmonth
dayofweek
decode
degrees
dense_rank
div
e
elt
encode
ewah_bitmap
ewah_bitmap_and
ewah_bitmap_empty
ewah_bitmap_or
exp
explode
field
find_in_set
first_value
floor
format_number
from_unixtime
from_utc_timestamp
get_json_object
greatest
hash
hex
histogram_numeric
hour
if
in
in_file
index
initcap
inline
instr
isnotnull
isnull
java_method
json_tuple
lag
last_day
last_value
lcase
lead
least
length
levenshtein
like
ln
locate
log
log10
log2
logged_in_user
lower
lpad
ltrim
map
map_keys
map_values
matchpath
max
md5
min
minute
month
months_between
named_struct
negative
next_day
ngrams
noop
noopstreaming
noopwithmap
noopwithmapstreaming
not
ntile
nvl
or
parse_url
parse_url_tuple
percent_rank
percentile
percentile_approx
pi
pmod
posexplode
positive
pow
power
printf
radians
rand
rank
reflect
reflect2
regexp
regexp_extract
regexp_replace
repeat
reverse
rlike
round
row_number
rpad
rtrim
second
sentences
sha2
sign
sin
size
sort_array
soundex
space
split
sqrt
stack
std
stddev
stddev_pop
stddev_samp
str_to_map
struct
substr
substring
sum
tan
to_date
to_unix_timestamp
to_utc_timestamp
translate
trim
trunc
ucase
unbase64
unhex
unix_timestamp
upper
uuid
var_pop
var_samp
variance
version
weekofyear
when
windowingtablefunction
xpath
xpath_boolean
xpath_double
xpath_float
xpath_int
xpath_long
xpath_number
xpath_short
xpath_string
year
|
~
Time taken: 2.927 seconds, Fetched: 219 row(s)
hive (default)> 

2）显示自带的函数的用法
desc function 函数名

hive> desc function upper;

hive (default)> desc function upper;
OK
tab_name
upper(str) - Returns str with all characters changed to uppercase
Time taken: 0.004 seconds, Fetched: 1 row(s)
hive (default)> 

3）详细显示自带的函数的用法

hive> desc function extended upper;

hive (default)> desc function extended upper;
OK
tab_name
upper(str) - Returns str with all characters changed to uppercase
Synonyms: ucase
Example:
  > SELECT upper('Facebook') FROM src LIMIT 1;
  'FACEBOOK'
Time taken: 0.007 seconds, Fetched: 5 row(s)
hive (default)>