DOUBLE

round(DOUBLE a)

Returns the roundedBIGINTvalue ofa.

返回對a四捨五入的BIGINT值

DOUBLE

round(DOUBLE a, INT d)

Returnsarounded toddecimal places.

返回DOUBLE型d的保留n位小數的DOUBLW型的近似值

BIGINT

floor(DOUBLE a)

Returns the maximumBIGINTvalue that is equal to or less thana

向下取整，最數軸上最接近要求的值的左邊的值 如：6.10->6 -3.4->-4

BIGINT

ceil(DOUBLE a), ceiling(DOUBLE a)

Returns the minimum BIGINT value that is equal to or greater thana.

求其不小於小給定實數的最小整數如：ceil(6) = ceil(6.1)= ceil(6.9) = 6

DOUBLE

rand(), rand(INT seed)

Returns a random number (that changes from row to row) that is distributed uniformly from 0 to 1. Specifying the seed will make sure the generated random number sequence is deterministic.

每行返回一個DOUBLE型隨機數seed是隨機因子

DOUBLE

exp(DOUBLE a), exp(DECIMAL a)

Returnseawhereeis the base of the natural logarithm. Decimal version added inHive 0.13.0.

返回e的a冪次方， a可為小數

DOUBLE

ln(DOUBLE a), ln(DECIMAL a)

Returns the natural logarithm of the argumenta. Decimal version added inHive 0.13.0.

以自然數為底d的對數，a可為小數

DOUBLE

log10(DOUBLE a), log10(DECIMAL a)

Returns the base-10 logarithm of the argumenta. Decimal version added inHive 0.13.0.

以10為底d的對數，a可為小數

DOUBLE

log2(DOUBLE a), log2(DECIMAL a)

Returns the base-2 logarithm of the argumenta. Decimal version added inHive 0.13.0.

以2為底數d的對數，a可為小數

DOUBLE

log(DOUBLE base, DOUBLE a)

log(DECIMAL base, DECIMAL a)

Returns the base-baselogarithm of the argumenta.Decimal versions added inHive 0.13.0.

以base為底的對數，base 與 a都是DOUBLE型別

DOUBLE

pow(DOUBLE a, DOUBLE p), power(DOUBLE a, DOUBLE p)

Returnsap.

計算a的p次冪

DOUBLE

sqrt(DOUBLE a), sqrt(DECIMAL a)

Returns the square root ofa. Decimal version added inHive 0.13.0.

計算a的平方根

STRING

bin(BIGINT a)

Returns the number in binary format (seehttp://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_bin).

計算二進位制a的STRING型別，a為BIGINT型別

STRING

hex(BIGINT a) hex(STRING a) hex(BINARY a)

If the argument is anINTorbinary,hexreturns the number as aSTRINGin hexadecimal format. Otherwise if the number is aSTRING, it converts each character into its hexadecimal representation and returns the resultingSTRING. (Seehttp://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_hex,BINARYversion as of Hive0.12.0.)

計算十六進位制a的STRING型別，如果a為STRING型別就轉換成字元相對應的十六進位制

BINARY

unhex(STRING a)

Inverse of hex. Interprets each pair of characters as a hexadecimal number and converts to the byte representation of the number. (BINARYversion as of Hive0.12.0, used to return a string.)

hex的逆方法

STRING

conv(BIGINT num, INT from_base, INT to_base), conv(STRING num, INT from_base, INT to_base)

Converts a number from a given base to another (seehttp://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_conv).

將GIGINT/STRING型別的num從from_base進位制轉換成to_base進位制

DOUBLE

abs(DOUBLE a)

Returns the absolute value.

計算a的絕對值

INT or DOUBLE

pmod(INT a, INT b), pmod(DOUBLE a, DOUBLE b)

Returns the positive value ofa mod b.

a對b取模

DOUBLE

sin(DOUBLE a), sin(DECIMAL a)

Returns the sine ofa(ais in radians). Decimal version added inHive 0.13.0.

求a的正弦值

DOUBLE

asin(DOUBLE a), asin(DECIMAL a)

Returns the arc sin ofaif -1<=a<=1 or NULL otherwise. Decimal version added inHive 0.13.0.

求d的反正弦值

DOUBLE

cos(DOUBLE a), cos(DECIMAL a)

Returns the cosine ofa(ais in radians). Decimal version added inHive 0.13.0.

求餘弦值

DOUBLE

acos(DOUBLE a), acos(DECIMAL a)

Returns the arccosine ofaif -1<=a<=1 or NULL otherwise. Decimal version added inHive 0.13.0.

求反餘弦值

DOUBLE

tan(DOUBLE a), tan(DECIMAL a)

Returns the tangent ofa(ais in radians). Decimal version added inHive 0.13.0.

求正切值

DOUBLE

atan(DOUBLE a), atan(DECIMAL a)

Returns the arctangent ofa. Decimal version added inHive 0.13.0.

求反正切值

DOUBLE

degrees(DOUBLE a), degrees(DECIMAL a)

Converts value ofafrom radians to degrees. Decimal version added inHive 0.13.0.

獎弧度值轉換角度值

DOUBLE

radians(DOUBLE a), radians(DOUBLE a)

Converts value ofafrom degrees to radians. Decimal version added inHive 0.13.0.

將角度值轉換成弧度值

INT or DOUBLE

positive(INT a), positive(DOUBLE a)

Returnsa.

返回a

INT or DOUBLE

negative(INT a), negative(DOUBLE a)

Returns-a.

返回a的相反數

DOUBLE or INT

sign(DOUBLE a), sign(DECIMAL a)

Returns the sign ofaas '1.0' (ifais positive) or '-1.0' (ifais negative), '0.0' otherwise. The decimal version returns INT instead of DOUBLE. Decimal version added inHive 0.13.0.

如果a是正數則返回1.0，是負數則返回-1.0，否則返回0.0

DOUBLE

e()

Returns the value ofe.

數學常數e

DOUBLE

pi()

Returns the value ofpi.

數學常數pi

INT BIGINT

shiftleft(TINYINT|SMALLINT|INT a, INT b)

shiftleft(BIGINT a, INTb)

Bitwise left shift (as of Hive1.2.0). Shiftsabpositions to the left.

Returns int for tinyint, smallint and inta. Returns bigint for biginta.

按位左移

INT

BIGINT

shiftright(TINYINT|SMALLINT|INT a, INTb)

shiftright(BIGINT a, INTb)

Bitwise right shift (as of Hive1.2.0). Shiftsabpositions to the right.

Returns int for tinyint, smallint and inta. Returns bigint for biginta.

按拉右移

INT

BIGINT

shiftrightunsigned(TINYINT|SMALLINT|INTa, INT b),

shiftrightunsigned(BIGINT a, INT b)

Bitwise unsigned right shift (as of Hive1.2.0).Shiftsabpositions to the right.

Returns int for tinyint, smallint and inta. Returns bigint for biginta.

無符號按位右移（<<<）

int

size(Map<K.V>)

Returns the number of elements in the map type.

求map的長度

int

size(Array<T>)

Returns the number of elements in the array type.

求陣列的長度

array<K>

map_keys(Map<K.V>)

Returns an unordered array containing the keys of the input map.

返回map中的所有key

array<V>

map_values(Map<K.V>)

Returns an unordered array containing the values of the input map.

返回map中的所有value

boolean

array_contains(Array<T>, value)

Returns TRUE if the array contains value.

如該陣列Array<T>包含value返回true。，否則返回false

array

sort_array(Array<T>)

Sorts the input array in ascending order according to the natural ordering of the array elements and returns it (as of version0.9.0).

按自然順序對陣列進行排序並返回

binary

binary(string|binary)

Casts the parameter into a binary.

將輸入的值轉換成二進位制

Expected "=" to follow "type"

cast(expr as <type>)

Converts the results of the expression expr to <type>. For example, cast('1' as BIGINT) will convert the string '1' to its integral representation. A null is returned if the conversion does not succeed. If cast(expr as boolean) Hive returns true for a non-empty string.

將expr轉換成type型別 如：cast("1" as BIGINT) 將字串1轉換成了BIGINT型別，如果轉換失敗將返回NULL

string

from_unixtime(bigint unixtime[, string format])

Converts the number of seconds from unix epoch (1970-01-01 00:00:00 UTC) to a string representing the timestamp of that moment in the current system time zone in the format of "1970-01-01 00:00:00".

將時間的秒值轉換成format格式（format可為“yyyy-MM-dd hh:mm:ss”,“yyyy-MM-dd hh”,“yyyy-MM-dd hh:mm”等等）如from_unixtime(1250111000,"yyyy-MM-dd") 得到2009-03-12

bigint

unix_timestamp()

Gets current Unix timestamp in seconds.

獲取本地時區下的時間戳

bigint

unix_timestamp(string date)

Converts time string in formatyyyy-MM-dd HH:mm:ssto Unix timestamp (in seconds), using the default timezone and the default locale, return 0 if fail: unix_timestamp('2009-03-20 11:30:01') = 1237573801

將格式為yyyy-MM-dd HH:mm:ss的時間字串轉換成時間戳 如unix_timestamp('2009-03-20 11:30:01') = 1237573801

bigint

unix_timestamp(string date, string pattern)

Convert time string with given pattern (see [http://docs.oracle.com/javase/tutorial/i18n/format/simpleDateFormat.html]) to Unix time stamp (in seconds), return 0 if fail: unix_timestamp('2009-03-20', 'yyyy-MM-dd') = 1237532400.

將指定時間字串格式字串轉換成Unix時間戳，如果格式不對返回0 如：unix_timestamp('2009-03-20', 'yyyy-MM-dd') = 1237532400

string

to_date(string timestamp)

Returns the date part of a timestamp string: to_date("1970-01-01 00:00:00") = "1970-01-01".

返回時間字串的日期部分

int

year(string date)

Returns the year part of a date or a timestamp string: year("1970-01-01 00:00:00") = 1970, year("1970-01-01") = 1970.

返回時間字串的年份部分

返回當前時間屬性哪個季度 如quarter('2015-04-08') = 2

int

month(string date)

Returns the month part of a date or a timestamp string: month("1970-11-01 00:00:00") = 11, month("1970-11-01") = 11.

返回時間字串的月份部分

int

day(string date) dayofmonth(date)

Returns the day part of a date or a timestamp string: day("1970-11-01 00:00:00") = 1, day("1970-11-01") = 1.

返回時間字串的天

int

hour(string date)

Returns the hour of the timestamp: hour('2009-07-30 12:58:59') = 12, hour('12:58:59') = 12.

返回時間字串的小時

int

minute(string date)

Returns the minute of the timestamp.

返回時間字串的分鐘

int

second(string date)

Returns the second of the timestamp.

返回時間字串的秒

int

weekofyear(string date)

Returns the week number of a timestamp string: weekofyear("1970-11-01 00:00:00") = 44, weekofyear("1970-11-01") = 44.

返回時間字串位於一年中的第幾個周內 如weekofyear("1970-11-01 00:00:00") = 44, weekofyear("1970-11-01") = 44

int

datediff(string enddate, string startdate)

Returns the number of days from startdate to enddate: datediff('2009-03-01', '2009-02-27') = 2.

計算開始時間startdate到結束時間enddate相差的天數

string

date_add(string startdate, int days)

Adds a number of days to startdate: date_add('2008-12-31', 1) = '2009-01-01'.

從開始時間startdate加上days

string

date_sub(string startdate, int days)

Subtracts a number of days to startdate: date_sub('2008-12-31', 1) = '2008-12-30'.

從開始時間startdate減去days

timestamp

from_utc_timestamp(timestamp, string timezone)

Assumes given timestamp is UTC and converts to given timezone (as of Hive0.8.0). For example, from_utc_timestamp('1970-01-01 08:00:00','PST') returns 1970-01-01 00:00:00.

如果給定的時間戳並非UTC，則將其轉化成指定的時區下時間戳

timestamp

to_utc_timestamp(timestamp, string timezone)

Assumes given timestamp is in given timezone and converts to UTC (as of Hive0.8.0). For example, to_utc_timestamp('1970-01-01 00:00:00','PST') returns 1970-01-01 08:00:00.

如果給定的時間戳指定的時區下時間戳，則將其轉化成UTC下的時間戳

Returns the current date at the start of query evaluation (as of Hive1.2.0). All calls of current_date within the same query return the same value.

返回當前時間日期

Returns the current timestamp at the start of query evaluation(as of Hive1.2.0). All calls of current_timestamp within the same query return the same value.

返回當前時間戳

Returns the date that is num_months after start_date(as of Hive1.1.0). start_date is a string, date or timestamp. num_months is an integer. The time part of start_date is ignored.If start_date is the last day of the month or if the resulting month has fewer days than the day component of start_date, then the result is the last day of the resulting month. Otherwise, the result has the same day component as start_date.

返回當前時間下再增加num_months個月的日期

返回這個月的最後一天的日期，忽略時分秒部分（HH:mm:ss）

返回當前時間的下一個星期X所對應的日期 如：next_day('2015-01-14', 'TU') = 2015-01-20 以2015-01-14為開始時間，其下一個星期二所對應的日期為2015-01-20

返回時間的最開始年份或月份 如trunc("2016-06-26",“MM”)=2016-06-01 trunc("2016-06-26",“YY”)=2016-01-01 注意所支援的格式為MONTH/MON/MM, YEAR/YYYY/YY

返回date1與date2之間相差的月份，如date1>date2，則返回正，如果date1<date2,則返回負，否則返回0.0 如：months_between('1997-02-28 10:30:00', '1996-10-30') = 3.94959677 1997-02-28 10:30:00與1996-10-30相差3.94959677個月

Converts a date/timestamp/string to a value of string in the format specified by the date format fmt (as of Hive1.2.0). Supported formats are Java SimpleDateFormat formats–https://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html. The second argument fmt should be constant. Example: date_format('2015-04-08', 'y') = '2015'.

date_format can be used to implement other UDFs, e.g.:

• dayname(date) is date_format(date, 'EEEE')
• dayofyear(date) is date_format(date, 'D')

  按指定格式返回時間date 如：date_format("2016-06-22","MM-dd")=06-22

T

if(boolean testCondition, T valueTrue, T valueFalseOrNull)

Returns valueTrue when testCondition is true, returns valueFalseOrNull otherwise.

如果testCondition 為true就返回valueTrue,否則返回valueFalseOrNull ，（valueTrue，valueFalseOrNull為泛型）

如果value值為NULL就返回default_value,否則返回value

T

COALESCE(T v1, T v2, ...)

Returns the first v that is not NULL, or NULL if all v's are NULL.

返回第一非null的值，如果全部都為NULL就返回NULL 如：COALESCE (NULL,44,55)=44/strong>

T

CASE a WHEN b THEN c [WHEN d THEN e]* [ELSE f] END

When a = b, returns c; when a = d, returns e; else returns f.

如果a=b就返回c,a=d就返回e，否則返回f 如CASE 4 WHEN 5 THEN 5 WHEN 4 THEN 4 ELSE 3 END 將返回4

T

CASE WHEN a THEN b [WHEN c THEN d]* [ELSE e] END

When a = true, returns b; when c = true, returns d; else returns e.

如果a=ture就返回b,c=ture就返回d，否則返回e 如：CASE WHEN 5>0 THEN 5 WHEN 4>0 THEN 4 ELSE 0 END 將返回5；CASE WHEN 5<0 THEN 5 WHEN 4<0 THEN 4 ELSE 0 END 將返回0

如果a為null就返回true，否則返回false

如果a為非null就返回true，否則返回false

int

ascii(string str)

Returns the numeric value of the first character of str.

返回str中首個ASCII字串的整數值

string

base64(binary bin)

Converts the argument from binary to a base 64 string (as of Hive0.12.0)..

將二進位制bin轉換成64位的字串

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. For example, concat('foo', 'bar') results in 'foobar'. Note that this function can take any number of input strings..

對二進位制位元組碼或字串按次序進行拼接

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". SeeStatisticsAndDataMiningfor more information..

與ngram類似，但context_ngram()允許你預算指定上下文(陣列)來去查詢子序列，具體看StatisticsAndDataMining(這裡的解釋更易懂)

string

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

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

與concat()類似，但使用指定的分隔符喜進行分隔

string

concat_ws(string SEP, array<string>)

Like concat_ws() above, but taking an array of strings. (as of Hive0.9.0).

拼接Array中的元素並用指定分隔符進行分隔

string

decode(binary bin, string charset)

Decodes 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 Hive0.12.0.).

使用指定的字符集charset將二進位制值bin解碼成字串，支援的字符集有：'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'，如果任意輸入引數為NULL都將返回NULL

binary

encode(string src, string charset)

Encodes 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 Hive0.12.0.).

使用指定的字符集charset將字串編碼成二進位制值，支援的字符集有：'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'，如果任一輸入引數為NULL都將返回NULL

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. For example, find_in_set('ab', 'abc,b,ab,c,def') returns 3..

返回以逗號分隔的字串中str出現的位置，如果引數str為逗號或查詢失敗將返回0，如果任一引數為NULL將返回NULL回

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 Hive0.10.0; bug with float types fixed inHive 0.14.0, decimal type support added inHive 0.14.0).

將數值X轉換成"#,###,###.##"格式字串，並保留d位小數，如果d為0，將進行四捨五入且不保留小數

string

get_json_object(string json_string, string path)

Extracts json object from a json string based on json path specified, and returns 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..

從指定路徑上的JSON字串抽取出JSON物件，並返回這個物件的JSON格式，如果輸入的JSON是非法的將返回NULL,注意此路徑上JSON字串只能由數字 字母 下劃線組成且不能有大寫字母和特殊字元，且key不能由數字開頭，這是由於Hive對列名的限制

boolean

in_file(string str, string filename)

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

如果檔名為filename的檔案中有一行資料與字串str匹配成功就返回true

int

instr(string str, string substr)

Returns the position of the first occurrence ofsubstrinstr. Returnsnullif either of the arguments arenulland returns0ifsubstrcould not be found instr. Be aware that this is not zero based. The first character instrhas index 1..

查詢字串str中子字串substr出現的位置，如果查詢失敗將返回0，如果任一引數為Null將返回null，注意位置為從1開始的

int

length(string A)

Returns the length of the string..

返回字串的長度

int

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

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

查詢字串str中的pos位置後字串substr第一次出現的位置

string

lower(string A) lcase(string A)

Returns the string resulting from converting all characters of B to lower case. For example, lower('fOoBaR') results in 'foobar'..

將字串A的所有字母轉換成小寫字母

string

lpad(string str, int len, string pad)

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

從左邊開始對字串str使用字串pad填充，最終len長度為止，如果字串str本身長度比len大的話，將去掉多餘的部分

string

ltrim(string A)

Returns the string resulting from trimming spaces from the beginning(left hand side) of A. For example, ltrim(' foobar ') results in 'foobar '..

去掉字串A前面的空格

array<struct<string,double>>

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

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

返回出現次數TOP K的的子序列,n表示子序列的長度，具體看StatisticsAndDataMining(這裡的解釋更易懂)

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. For example, 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, for example, parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'QUERY', 'k1') returns 'v1'..

返回從URL中抽取指定部分的內容，引數url是URL字串，而引數partToExtract是要抽取的部分，這個引數包含(HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, and USERINFO,例如：parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'HOST') ='facebook.com'，如果引數partToExtract值為QUERY則必須指定第三個引數key 如：parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'QUERY', 'k1') =‘v1’

string

printf(String format, Obj... args)

Returns the input formatted according do printf-style format strings (as of Hive0.9.0)..

按照printf風格格式輸出字串

string

regexp_extract(string subject, string pattern, int index)

Returns the string extracted using the pattern. For example, 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..

抽取字串subject中符合正則表示式pattern的第index個部分的子字串，注意些預定義字元的使用，如第二個引數如果使用'\s'將被匹配到s,'\\s'才是匹配空格

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. For example, 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..

按照Java正則表示式PATTERN將字串INTIAL_STRING中符合條件的部分成REPLACEMENT所指定的字串，如裡REPLACEMENT這空的話，抽符合正則的部分將被去掉 如：regexp_replace("foobar", "oo|ar", "") = 'fb.'注意些預定義字元的使用，如第二個引數如果使用'\s'將被匹配到s,'\\s'才是匹配空格

string

repeat(string str, int n)

Repeats str n times..

重複輸出n次字串str

string

reverse(string A)

Returns the reversed string..

反轉字串

string

rpad(string str, int len, string pad)

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

從右邊開始對字串str使用字串pad填充，最終len長度為止，如果字串str本身長度比len大的話，將去掉多餘的部分

string

rtrim(string A)

Returns the string resulting from trimming spaces from the end(right hand side) of A. For example, rtrim(' foobar ') results in ' foobar'..

去掉字串後面出現的空格

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. For example, sentences('Hello there! How are you?') returns ( ("Hello", "there"), ("How", "are", "you") )..

字串str將被轉換成單詞陣列，如：sentences('Hello there! How are you?') =( ("Hello", "there"), ("How", "are", "you") )

string

space(int n)

Returns a string of n spaces..

返回n個空格

array

split(string str, string pat)

Splits str around pat (pat is a regular expression)..

按照正則表示式pat來分割字串str,並將分割後的陣列字串的形式返回

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..

將字串str按照指定分隔符轉換成Map，第一個引數是需要轉換字串，第二個引數是鍵值對之間的分隔符，預設為逗號;第三個引數是鍵值之間的分隔符，預設為"="

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. For example, substr('foobar', 4) results in 'bar' (see [http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr])..

對於字串A,從start位置開始擷取字串並返回

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. For example, substr('foobar', 4, 1) results in 'b' (see [http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr])..

對於二進位制/字串A,從start位置開始擷取長度為length的字串並返回

擷取第count分隔符之前的字串，如count為正則從左邊開始擷取，如果為負則從右邊開始擷取

string

translate(string|char|varchar input, string|char|varchar from, string|char|varchar to)

Translates the input string by replacing the characters present in thefromstring with the corresponding characters in thetostring. This is similar to thetranslatefunction inPostgreSQL. If any of the parameters to this UDF are NULL, the result is NULL as well. (Available as of Hive0.10.0, for string types)

Char/varchar support added as ofHive 0.14.0..

將input出現在from中的字串替換成to中的字串 如：translate("MOBIN","BIN","M")="MOM"

string

trim(string A)

Returns the string resulting from trimming spaces from both ends of A. For example, trim(' foobar ') results in 'foobar'.

將字串A前後出現的空格去掉

binary

unbase64(string str)

Converts the argument from a base 64 string to BINARY. (As of Hive0.12.0.).

將64位的字串轉換二進位制值

string

upper(string A) ucase(string A)

Returns the string resulting from converting all characters of A to upper case. For example, upper('fOoBaR') results in 'FOOBAR'..

將字串A中的字母轉換成大寫字母

將字串A轉換第一個字母大寫其餘字母的字串

計算兩個字串之間的差異大小 如：levenshtein('kitten', 'sitting') = 3

將普通字串轉換成soundex字串

BIGINT

count(*), count(expr), count(DISTINCT expr[, expr...])

count(*) - Returns the total number of retrieved rows, including rows containing NULL values.

統計總行數，包括含有NULL值的行

count(expr) - Returns the number of rows for which the supplied expression is non-NULL.

統計提供非NULL的expr表示式值的行數

count(DISTINCT expr[, expr]) - Returns the number of rows for which the supplied expression(s) are unique and non-NULL. Execution of this can be optimized withhive.optimize.distinct.rewrite.

統計提供非NULL且去重後的expr表示式值的行數

DOUBLE

sum(col), sum(DISTINCT col)

Returns the sum of the elements in the group or the sum of the distinct values of the column in the group.

sum(col),表示求指定列的和，sum(DISTINCT col)表示求去重後的列的和

DOUBLE

avg(col), avg(DISTINCT col)

Returns the average of the elements in the group or the average of the distinct values of the column in the group.

avg(col),表示求指定列的平均值，avg(DISTINCT col)表示求去重後的列的平均值

DOUBLE

min(col)

Returns the minimum of the column in the group.

求指定列的最小值

DOUBLE

max(col)

Returns the maximum value of the column in the group.

求指定列的最大值

DOUBLE

variance(col), var_pop(col)

Returns the variance of a numeric column in the group.

求指定列數值的方差

DOUBLE

var_samp(col)

Returns the unbiased sample variance of a numeric column in the group.

求指定列數值的樣本方差

DOUBLE

stddev_pop(col)

Returns the standard deviation of a numeric column in the group.

求指定列數值的標準偏差

DOUBLE

stddev_samp(col)

Returns the unbiased sample standard deviation of a numeric column in the group.

求指定列數值的樣本標準偏差

DOUBLE

covar_pop(col1, col2)

Returns the population covariance of a pair of numeric columns in the group.

求指定列數值的協方差

DOUBLE

covar_samp(col1, col2)

Returns the sample covariance of a pair of a numeric columns in the group.

求指定列數值的樣本協方差

DOUBLE

corr(col1, col2)

Returns the Pearson coefficient of correlation of a pair of a numeric columns in the group.

返回兩列數值的相關係數

DOUBLE

percentile(BIGINT col, p)

Returns the exact p^thpercentile of a column in the group (does not work with floating point types). p must be between 0 and 1. NOTE: A true percentile can only be computed for integer values. Use PERCENTILE_APPROX if your input is non-integral.

返回col的p%分位數

Array Type

explode(array<TYPE> a)

For each element in a, generates a row containing that element.

對於a中的每個元素，將生成一行且包含該元素

N rows

explode(ARRAY)

Returns one row for each element from the array..

每行對應陣列中的一個元素

N rows

explode(MAP)

Returns one row for each key-value pair from the input map with two columns in each row: one for the key and another for the value. (As of Hive0.8.0.).

每行對應每個map鍵-值，其中一個欄位是map的鍵，另一個欄位是map的值

N rows

posexplode(ARRAY)

Behaves likeexplodefor arrays, but includes the position of items in the original array by returning a tuple of(pos, value). (As ofHive 0.13.0.).

與explode類似，不同的是還返回各元素在陣列中的位置

N rows

stack(INT n, v_1, v_2, ..., v_k)

Breaks up v_1, ..., v_k into n rows. Each row will have k/n columns. n must be constant..

把M列轉換成N行，每行有M/N個欄位，其中n必須是個常數

tuple

json_tuple(jsonStr, k1, k2, ...)

Takes a set of names (keys) and a JSON string, and returns a tuple of values. This is a more efficient version of theget_json_objectUDF because it can get multiple keys with just one call..

從一個JSON字串中獲取多個鍵並作為一個元組返回，與get_json_object不同的是此函式能一次獲取多個鍵值

tuple

parse_url_tuple(url, p1, p2, ...)

This is similar to theparse_url()UDF but can extract multiple parts at once out of a URL. Valid part names are: HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, USERINFO, QUERY:<KEY>..

返回從URL中抽取指定N部分的內容，引數url是URL字串，而引數p1,p2,....是要抽取的部分，這個引數包含HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, USERINFO, QUERY:<KEY>

inline(ARRAY<STRUCT[,STRUCT]>)

Explodes an array of structs into a table. (As of Hive0.10.).

將結構體陣列提取出來並插入到表中