hive常用函数

int

ascii(string str)

Returns the numeric value of the first character of str

string

base64(binary bin)

Convert the argument from binary to a base 64 string (as of Hive 0.12.0)

string

concat(string|binary A, string|binary B...)

Returns the string or bytes resulting from concatenating the strings or bytes passed in as parameters in order. e.g. concat(‘foo‘, ‘bar‘) results in ‘foobar‘. Note that this function can take any number of input strings.

array<struct<string,double>>

context_ngrams(array<array<string>>, array<string>, int K, int pf)

Returns the top-k contextual N-grams from a set of tokenized sentences, given a string of "context". See StatisticsAndDataMining for more information.

string

concat_ws(string SEP, string A, string B...)

Like concat() above, but with custom separator SEP.

string

concat_ws(string SEP, array<string>)

Like concat_ws() above, but taking an array of strings. (as of Hive 0.9.0)

string

decode(binary bin, string charset)

Decode the first argument into a String using the provided character set (one of ‘US_ASCII‘, ‘ISO-8859-1‘, ‘UTF-8‘, ‘UTF-16BE‘, ‘UTF-16LE‘, ‘UTF-16‘). If either argument is null, the result will also be null. (as of Hive 0.12.0)

binary

encode(string src, string charset)

Encode the first argument into a BINARY using the provided character set (one of ‘US_ASCII‘, ‘ISO-8859-1‘, ‘UTF-8‘, ‘UTF-16BE‘, ‘UTF-16LE‘, ‘UTF-16‘). If either argument is null, the result will also be null. (as of Hive 0.12.0)

int

find_in_set(string str, string strList)

Returns the first occurance of str in strList where strList is a comma-delimited string. Returns null if either argument is null. Returns 0 if the first argument contains any commas. e.g. find_in_set(‘ab‘, ‘abc,b,ab,c,def‘) returns 3

string

format_number(number x, int d)

Formats the number X to a format like ‘#,###,###.##‘, rounded to D decimal places, and returns the result as a string. If D is 0, the result has no decimal point or fractional part. (as of Hive 0.10.0)

string

get_json_object(string json_string, string path)

Extract json object from a json string based on json path specified, and return json string of the extracted json object. It will return null if the input json string is invalid. NOTE: The json path can only have the characters [0-9a-z_], i.e., no upper-case or special characters. Also, the keys *cannot start with numbers.* This is due to restrictions on Hive column names.

boolean

in_file(string str, string filename)

Returns true if the string str appears as an entire line in filename.

int

instr(string str, string substr)

Returns the position of the first occurrence of substr in str. Returns null if either of the arguments are null and returns 0 if substr could not be found in str. Be aware that this is not zero based. The first character in str has index 1.

int

length(string A)

Returns the length of the string

int

locate(string substr, string str[, int pos])

Returns the position of the first occurrence of substr in str after position pos

string

lower(string A) lcase(string A)

Returns the string resulting from converting all characters of B to lower case e.g. lower(‘fOoBaR‘) results in ‘foobar‘

string

lpad(string str, int len, string pad)

Returns str, left-padded with pad to a length of len

string

ltrim(string A)

Returns the string resulting from trimming spaces from the beginning(left hand side) of A e.g. ltrim(‘ foobar ‘) results in ‘foobar ‘

array<struct<string,double>>

ngrams(array<array<string>>, int N, int K, int pf)

Returns the top-k N-grams from a set of tokenized sentences, such as those returned by the sentences() UDAF. See StatisticsAndDataMining for more information.

string

parse_url(string urlString, string partToExtract [, string keyToExtract])

Returns the specified part from the URL. Valid values for partToExtract include HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, and USERINFO. e.g. parse_url(‘http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1‘, ‘HOST‘) returns ‘facebook.com‘. Also a value of a particular key in QUERY can be extracted by providing the key as the third argument, e.g. parse_url(‘http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1‘, ‘QUERY‘, ‘k1‘) returns ‘v1‘.

string

printf(String format, Obj... args)

Returns the input formatted according do printf-style format strings (as of Hive 0.9.0)

string

regexp_extract(string subject, string pattern, int index)

Returns the string extracted using the pattern. e.g. regexp_extract(‘foothebar‘, ‘foo(.*?)(bar)‘, 2) returns ‘bar.‘ Note that some care is necessary in using predefined character classes: using ‘\s‘ as the second argument will match the letter s; ‘
s‘ is necessary to match whitespace, etc. The ‘index‘ parameter is the Java regex Matcher group() method index. See docs/api/java/util/regex/Matcher.html for more information on the ‘index‘ or Java regex group() method.

string

regexp_replace(string INITIAL_STRING, string PATTERN, string REPLACEMENT)

Returns the string resulting from replacing all substrings in INITIAL_STRING that match the java regular expression syntax defined in PATTERN with instances of REPLACEMENT, e.g. regexp_replace("foobar", "oo|ar", "") returns ‘fb.‘ Note that some care is necessary in using predefined character classes: using ‘\s‘ as the second argument will match the letter s; ‘
s‘ is necessary to match whitespace, etc.

string

repeat(string str, int n)

Repeat str n times

string

reverse(string A)

Returns the reversed string

string

rpad(string str, int len, string pad)

Returns str, right-padded with pad to a length of len

string

rtrim(string A)

Returns the string resulting from trimming spaces from the end(right hand side) of A e.g. rtrim(‘ foobar ‘) results in ‘ foobar‘

array<array<string>>

sentences(string str, string lang, string locale)

Tokenizes a string of natural language text into words and sentences, where each sentence is broken at the appropriate sentence boundary and returned as an array of words. The ‘lang‘ and ‘locale‘ are optional arguments. e.g. sentences(‘Hello there! How are you?‘) returns ( ("Hello", "there"), ("How", "are", "you") )

string

space(int n)

Return a string of n spaces

array

split(string str, string pat)

Split str around pat (pat is a regular expression)

map<string,string>

str_to_map(text[, delimiter1, delimiter2])

Splits text into key-value pairs using two delimiters. Delimiter1 separates text into K-V pairs, and Delimiter2 splits each K-V pair. Default delimiters are ‘,‘ for delimiter1 and ‘=‘ for delimiter2.

string

substr(string|binary A, int start) substring(string|binary A, int start)

Returns the substring or slice of the byte array of A starting from start position till the end of string A e.g. substr(‘foobar‘, 4) results in ‘bar‘ (see [http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr])

string

substr(string|binary A, int start, int len) substring(string|binary A, int start, int len)

Returns the substring or slice of the byte array of A starting from start position with length len e.g. substr(‘foobar‘, 4, 1) results in ‘b‘ (see [http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr])

string

translate(string input, string from, string to)

Translates the input string by replacing the characters present in the from string with the corresponding characters in the to string. This is similar to the translate function in PostgreSQL. If any of the parameters to this UDF are NULL, the result is NULL as well (available as of Hive 0.10.0)

string

trim(string A)

Returns the string resulting from trimming spaces from both ends of A e.g. trim(‘ foobar ‘) results in ‘foobar‘

binary

unbase64(string str)

Convert the argument from a base 64 string to BINARY (as of Hive 0.12.0)

string

upper(string A) ucase(string A)

Returns the string resulting from converting all characters of A to upper case e.g. upper(‘fOoBaR‘) results in ‘FOOBAR‘