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Hive常用函数大全（一）（关系/数学/逻辑/数值/日期/条件/字符串/集合统计/复杂类型）

發布時間：2023/12/16 编程问答 19 豆豆

生活随笔收集整理的這篇文章主要介紹了 Hive常用函数大全（一）（关系/数学/逻辑/数值/日期/条件/字符串/集合统计/复杂类型）小編覺得挺不錯的,現在分享給大家,幫大家做個參考.

https://blog.csdn.net/scgaliguodong123_/article/details/60881166

測試數據集：

create external table if not exists order_detail( user_id string, device_id string, user_type string, price double, sales int ) row format delimited fields terminated by '\t' lines terminated by '\n' stored as textfile;hdfs dfs -put /home/liguodong/data/data.text /temp/lgdload data inpath '/temp/lgd/data.text' overwrite into table order_detail;select * from order_detail; +----------+-------------+------------+--------+--------+--+ | user_id | device_id | user_type | price | sales | +----------+-------------+------------+--------+--------+--+ | zhangsa | dfsadsa323 | new | 67.1 | 2 | | lisi | 543gfd | old | 43.32 | 1 | | wanger | 65ghf | new | 88.88 | 3 | | liiu | fdsfagwe | new | 66.0 | 1 | | qibaqiu | fds | new | 54.32 | 1 | | wangshi | f332 | old | 77.77 | 2 | | liwei | hfd | old | 88.44 | 3 | | wutong | 543gdfsd | new | 56.55 | 6 | | lilisi | dsfgg | new | 88.88 | 5 | | qishili | fds | new | 66.66 | 5 | +----------+-------------+------------+--------+--------+--+

關系運算

## > < = ##注意： String 的比較要注意(常用的時間比較可以先 to_date 之后再比較) select long_time>short_time, long_time<short_time,long_time=short_time, to_date(long_time)=to_date(short_time) from (select '2017-01-11 00:00:00' as long_time, '2017-01-11' as short_timefrom order_detail limit 1 )bb;result: true false false true## 空值判斷 select 1 from order_detail where NULL is NULL limit 1;## 非空判斷 select 1 from order_detail where 1 is not NULL limit 1;## LIKE 語法: A LIKE B 描述: 字符串A符合表達式B的正則語法,則為TRUE;否則為FALSE. B中字符”_”表示任意單個字符，而字符”%”表示任意數量的字符。select user_id from order_detail where user_id like 'li%';+----------+--+ | user_id | +----------+--+ | lisi | | liiu | | liwei | | lilisi | +----------+--+select user_id from order_detail where user_id like 'li__';+----------+--+ | user_id | +----------+--+ | lisi | | liiu | +----------+--+## RLIKE 語法: A RLIKE B 描述: 字符串A符合JAVA正則表達式 B 的正則語法，則為 TRUE；否則為 FALSE。select user_id from order_detail where user_id rlike '^l.*i$';+----------+--+ | user_id | +----------+--+ | lisi | | liwei | | lilisi | +----------+--+select device_id from order_detail where device_id rlike '^\\w+$';+-------------+--+ | device_id | +-------------+--+ | dfsadsa323 | | 543gfd | | 65ghf | | fdsfagwe | | fds | | f332 | | hfd | | 543gdfsd | | dsfgg | | fds | +-------------+--+select device_id from order_detail where device_id rlike '^[a-zA-Z]+$';+------------+--+ | device_id | +------------+--+ | fdsfagwe | | fds | | hfd | | dsfgg | | fds | +------------+--+select device_id from order_detail where device_id rlike '^[a-zA-Z]{4,}$';+------------+--+ | device_id | +------------+--+ | fdsfagwe | | dsfgg | +------------+--+## REGEXP 語法: A REGEXP B 描述: 功能與 RLIKE 相同 select device_id from order_detail where device_id REGEXP '^[a-zA-Z]{4,}$';+------------+--+ | device_id | +------------+--+ | fdsfagwe | | dsfgg | +------------+--+

數學運算

## + - * / 注意： hive中最高精度的數據類型是 double,只精確到小數點后16位，在做除法運算的時候要特別注意select user_id,100-price,sales-1,price*sales,price/sales, ceil(28.0/6.999999999999999999999),ceil(28.0/6.99999999999999), price%sales from order_detail;+----------+---------------------+------+---------------------+---------------------+------+------+---------------------+--+ | user_id | _c1 | _c2 | _c3 | _c4 | _c5 | _c6 | _c7 | +----------+---------------------+------+---------------------+---------------------+------+------+---------------------+--+ | zhangsa | 32.900000000000006 | 1 | 134.2 | 33.55 | 4 | 5 | 1.0999999999999943 | | lisi | 56.68 | 0 | 43.32 | 43.32 | 4 | 5 | 0.3200000000000003 | | wanger | 11.120000000000005 | 2 | 266.64 | 29.626666666666665 | 4 | 5 | 1.8799999999999955 | | liiu | 34.0 | 0 | 66.0 | 66.0 | 4 | 5 | 0.0 | | qibaqiu | 45.68 | 0 | 54.32 | 54.32 | 4 | 5 | 0.3200000000000003 | | wangshi | 22.230000000000004 | 1 | 155.54 | 38.885 | 4 | 5 | 1.769999999999996 | | liwei | 11.560000000000002 | 2 | 265.32 | 29.48 | 4 | 5 | 1.4399999999999977 | | wutong | 43.45 | 5 | 339.29999999999995 | 9.424999999999999 | 4 | 5 | 2.549999999999997 | | lilisi | 11.120000000000005 | 4 | 444.4 | 17.776 | 4 | 5 | 3.8799999999999955 | | qishili | 33.34 | 4 | 333.29999999999995 | 13.331999999999999 | 4 | 5 | 1.6599999999999966 | +----------+---------------------+------+---------------------+---------------------+------+------+---------------------+--+## % 注意：精度在 hive 中是個很大的問題，類似這樣的操作最好通過 round 指定精度 select 8.4 % 4,round(8.4 % 4 , 2) from order_detail limit 1;+----------------------+------+--+ | _c0 | _c1 | +----------------------+------+--+ | 0.40000000000000036 | 0.4 | +----------------------+------+--+## 位與& 位或| 位異或^ 位取反~select 4&6, 8&4, 4|8,6|8,4^8,6^4,~6,~3 from order_detail limit 1;

邏輯運算

數值計算函數

## 取整: round 語法: round(double a) 說明: 遵循四舍五入## 指定精度取整: round 語法: round(double a, int d)## 向下取整: floor 說明: 返回等于或者小于該 double 變量的最大的整數## 向上取整: ceil 說明: 返回等于或者大于該 double 變量的最小的整數## 向上取整: ceiling 說明: 與ceil功能相同select user_id,price,round(price),round(price,0),round(price,1),floor(price),ceil(price),ceiling(price) from order_detail;+----------+--------+-------+-------+-------+------+------+------+--+ | user_id | price | _c2 | _c3 | _c4 | _c5 | _c6 | _c7 | +----------+--------+-------+-------+-------+------+------+------+--+ | zhangsa | 67.1 | 67.0 | 67.0 | 67.1 | 67 | 68 | 68 | | lisi | 43.32 | 43.0 | 43.0 | 43.3 | 43 | 44 | 44 | | wanger | 88.88 | 89.0 | 89.0 | 88.9 | 88 | 89 | 89 | | liiu | 66.0 | 66.0 | 66.0 | 66.0 | 66 | 66 | 66 | | qibaqiu | 54.32 | 54.0 | 54.0 | 54.3 | 54 | 55 | 55 | | wangshi | 77.77 | 78.0 | 78.0 | 77.8 | 77 | 78 | 78 | | liwei | 88.44 | 88.0 | 88.0 | 88.4 | 88 | 89 | 89 | | wutong | 56.55 | 57.0 | 57.0 | 56.6 | 56 | 57 | 57 | | lilisi | 88.88 | 89.0 | 89.0 | 88.9 | 88 | 89 | 89 | | qishili | 66.66 | 67.0 | 67.0 | 66.7 | 66 | 67 | 67 | +----------+--------+-------+-------+-------+------+------+------+--+## 取隨機數: rand 說明: 返回一個 0 到 1 范圍內的隨機數。如果指定種子 seed(整數)，則會得到一個穩定的隨機數序列。## 自然指數: exp 自然對數: lnselect user_id,sales,price,rand(),rand(sales),exp(sales),ln(price) from order_detail;+----------+--------+--------+----------------------+----------------------+---------------------+---------------------+--+ | user_id | sales | price | _c3 | _c4 | _c5 | _c6 | +----------+--------+--------+----------------------+----------------------+---------------------+---------------------+--+ | zhangsa | 2 | 67.1 | 0.708066911383928 | 0.7311469360199058 | 7.38905609893065 | 4.206184043977636 | | lisi | 1 | 43.32 | 0.509552420396184 | 0.9014476240300544 | 2.718281828459045 | 3.76861442213279 | | wanger | 3 | 88.88 | 0.2462642074705902 | 0.49682259343089075 | 20.085536923187668 | 4.487287145331375 | | liiu | 1 | 66.0 | 0.720800913818751 | 0.9858769332362016 | 2.718281828459045 | 4.189654742026425 | | qibaqiu | 1 | 54.32 | 0.7358273250797408 | 0.8571240443456863 | 2.718281828459045 | 3.9948924832504407 | | wangshi | 2 | 77.77 | 0.11092554405907218 | 0.9874208338984266 | 7.38905609893065 | 4.353755752706852 | | liwei | 3 | 88.44 | 0.5162574691353392 | 0.2281579303734177 | 20.085536923187668 | 4.482324355989245 | | wutong | 6 | 56.55 | 0.2753658209591686 | 0.07479382813444624 | 403.4287934927351 | 4.03512520256213 | | lilisi | 5 | 88.88 | 0.25777632824045826 | 0.7431577182910525 | 148.4131591025766 | 4.487287145331375 | | qishili | 5 | 66.66 | 0.06419187859857822 | 0.9495832704567262 | 148.4131591025766 | 4.199605072879594 | +----------+--------+--------+----------------------+----------------------+---------------------+---------------------+--+## 以10為底對數: log10 以2為底對數: log2 ## 對數: log 語法: log(double base, double a) 說明: 返回以 base 為底的 a 的對數select log10(100),log2(8),log(4,256) from order_detail limit 1;+------+------+------+--+ | _c0 | _c1 | _c2 | +------+------+------+--+ | 2.0 | 3.0 | 4.0 | +------+------+------+--+## 冪運算: pow power 開平方: sqrtselect pow(2,4), power(2,4),sqrt(16) from order_detail limit 1;+-------+-------+------+--+ | _c0 | _c1 | _c2 | +-------+-------+------+--+ | 16.0 | 16.0 | 4.0 | +-------+-------+------+--+## 二進制: bin 十六進制: hex 反轉十六進制: unhex ## 進制轉換: conv 語法: conv(BIGINT num, int from_base, int to_base) 說明: 將數值 num 從 from_base 進制轉化到 to_base 進制select bin(7),hex('19'),hex('abc'),unhex('616263'),unhex('41'),conv(17,10,16),conv(17,10,2) from order_detail limit 1;+------+-------+---------+------+------+------+--------+--+ | _c0 | _c1 | _c2 | _c3 | _c4 | _c5 | _c6 | +------+-------+---------+------+------+------+--------+--+ | 111 | 3139 | 616263 | abc | A | 11 | 10001 | +------+-------+---------+------+------+------+--------+--+## 絕對值:abs 正取余:pmod 正弦:sin 反正弦:asin 余弦:cos 反余弦:acos 返回A的值:positive 返回A的相反數:negativeselect abs(-13),abs(10.10),pmod(9,4),pmod(-9,4), sin(0.8),asin(0.7173560908995228),cos(0.9), acos(0.6216099682706644), positive(-10),negative(-10) from order_detail limit 1;+------+-------+------+------+---------------------+------+---------------------+------+------+------+--+ | _c0 | _c1 | _c2 | _c3 | _c4 | _c5 | _c6 | _c7 | _c8 | _c9 | +------+-------+------+------+---------------------+------+---------------------+------+------+------+--+ | 13 | 10.1 | 1 | 3 | 0.7173560908995228 | 0.8 | 0.6216099682706644 | 0.9 | -10 | 10 | +------+-------+------+------+---------------------+------+---------------------+------+------+------+--+

日期函數

## UNIX時間戳轉日期: from_unixtime## 日期轉UNIX時間戳,指定格式日期轉UNIX 時間戳,獲取當前UNIX時間戳: unix_timestamp 說明: 轉換格式為"yyyy-MM-dd HH:mm:ss"的日期到 UNIX 時間戳。如果轉化失敗，則返回 0。select from_unixtime(1323308943),from_unixtime(1323308943,'yyyyMMdd'),unix_timestamp(),unix_timestamp('2017-12-07 16:01:03'),unix_timestamp('20171207 16-01-03','yyyyMMdd HH-mm-ss') from order_detail limit 1; +----------------------+-----------+-------------+-------------+-------------+--+ | _c0 | _c1 | _c2 | _c3 | _c4 | +----------------------+-----------+-------------+-------------+-------------+--+ | 2011-12-08 09:49:03 | 20111208 | 1489029488 | 1512633663 | 1512633663 | +----------------------+-----------+-------------+-------------+-------------+--+## 日期時間轉日期:to_date 日期轉年:year 日期轉月:month 日期轉天:day 日期轉小時:hour 日期轉分鐘:minute 日期轉秒:secondselect to_date('2016-12-08 10:03:01'), year('2016-12-08 10:03:01'), month('2016-12-08'), day('2016-12-08 10:03:01'), hour('2016-12-08 10:03:01'), minute('2016-12-08 10:03:01'), second('2016-12-08 10:03:01') from order_detail limit 1; +-------------+-------+------+------+------+------+------+--+ | _c0 | _c1 | _c2 | _c3 | _c4 | _c5 | _c6 | +-------------+-------+------+------+------+------+------+--+ | 2016-12-08 | 2016 | 12 | 8 | 10 | 3 | 1 | +-------------+-------+------+------+------+------+------+--+## 日期轉周:weekofyear 日期比較:datediff select weekofyear('2016-12-08 10:03:01'), datediff('2016-12-08','2016-11-27') from order_detail limit 1;+------+------+--+ | _c0 | _c1 | +------+------+--+ | 49 | 11 | +------+------+--+## 日期增加: date_add 日期減少: date_sub select date_add('2016-12-08',10),date_add('2016-12-08',-10), date_sub('2016-12-08',-10),date_sub('2016-12-08',10) from order_detail limit 1;+-------------+-------------+-------------+-------------+--+ | _c0 | _c1 | _c2 | _c3 | +-------------+-------------+-------------+-------------+--+ | 2016-12-18 | 2016-11-28 | 2016-12-18 | 2016-11-28 | +-------------+-------------+-------------+-------------+--+select date_add('20161208',10), from_unixtime(unix_timestamp(date_add('2016-12-08',10)),'yyyyMMdd'), from_unixtime(unix_timestamp(date_add('2016-12-08',10),'yyyy-MM-dd'),'yyyyMMdd') from order_detail limit 1;+-------+-------+-----------+--+ | _c0 | _c1 | _c2 | +-------+-------+-----------+--+ | NULL | NULL | 20161218 | +-------+-------+-----------+--+

條件函數

## IF CASE COALESCE 說明: COALESCE返回參數中的第一個非空值；如果所有值都為 NULL，那么返回 NULLselect user_id,device_id,user_type,sales, if(user_type='new',user_id,'***'), COALESCE(null,user_id,device_id,user_type), COALESCE(null,null,device_id,user_type), case user_type when 'new' then 'new_user' when 'old' then 'old_user' else 'others' end, case when user_type='new' and sales>=5 then 'gold_user' when user_type='old' and sales<3 then 'bronze_user' else 'silver_user' end from order_detail;+----------+-------------+------------+--------+----------+----------+-------------+-----------+--------------+--+ | user_id | device_id | user_type | sales | _c4 | _c5 | _c6 | _c7 | _c8 | +----------+-------------+------------+--------+----------+----------+-------------+-----------+--------------+--+ | zhangsa | dfsadsa323 | new | 2 | zhangsa | zhangsa | dfsadsa323 | new_user | silver_user | | lisi | 543gfd | old | 1 | *** | lisi | 543gfd | old_user | bronze_user | | wanger | 65ghf | new | 3 | wanger | wanger | 65ghf | new_user | silver_user | | liiu | fdsfagwe | new | 1 | liiu | liiu | fdsfagwe | new_user | silver_user | | qibaqiu | fds | new | 1 | qibaqiu | qibaqiu | fds | new_user | silver_user | | wangshi | f332 | old | 2 | *** | wangshi | f332 | old_user | bronze_user | | liwei | hfd | old | 3 | *** | liwei | hfd | old_user | silver_user | | wutong | 543gdfsd | new | 6 | wutong | wutong | 543gdfsd | new_user | gold_user | | lilisi | dsfgg | new | 5 | lilisi | lilisi | dsfgg | new_user | gold_user | | qishili | fds | new | 5 | qishili | qishili | fds | new_user | gold_user | +----------+-------------+------------+--------+----------+----------+-------------+-----------+--------------+--+

字符串函數

## 字符串長度:length 字符串反轉:reverse 字符串連接:concat 帶分隔符字符串連接:concat_wsselect user_id,device_id,user_type,length(user_id),reverse(user_id), concat(user_id,device_id,user_type),concat_ws('_',user_id,device_id,user_type) from order_detail;+----------+-------------+------------+------+----------+-----------------------+-------------------------+--+ | user_id | device_id | user_type | _c3 | _c4 | _c5 | _c6 | +----------+-------------+------------+------+----------+-----------------------+-------------------------+--+ | zhangsa | dfsadsa323 | new | 7 | asgnahz | zhangsadfsadsa323new | zhangsa_dfsadsa323_new | | lisi | 543gfd | old | 4 | isil | lisi543gfdold | lisi_543gfd_old | | wanger | 65ghf | new | 6 | regnaw | wanger65ghfnew | wanger_65ghf_new | | liiu | fdsfagwe | new | 4 | uiil | liiufdsfagwenew | liiu_fdsfagwe_new | | qibaqiu | fds | new | 7 | uiqabiq | qibaqiufdsnew | qibaqiu_fds_new | | wangshi | f332 | old | 7 | ihsgnaw | wangshif332old | wangshi_f332_old | | liwei | hfd | old | 5 | iewil | liweihfdold | liwei_hfd_old | | wutong | 543gdfsd | new | 6 | gnotuw | wutong543gdfsdnew | wutong_543gdfsd_new | | lilisi | dsfgg | new | 6 | isilil | lilisidsfggnew | lilisi_dsfgg_new | | qishili | fds | new | 7 | ilihsiq | qishilifdsnew | qishili_fds_new |## 字符串截取函數： substr,substring 語法: substr(string A, int start),substring(string A, int start) 說明：返回字符串 A 從 start 位置到結尾的字符串語法: substr(string A, int start, int len),substring(string A, int start, int len) 說明：返回字符串A從start位置開始，長度為len的字符串select user_id,substr(user_id,3),substr(user_id,-2), substring(user_id,1,2),substr(user_id,-2,2) from order_detail;+----------+--------+------+------+------+--+ | user_id | _c1 | _c2 | _c3 | _c4 | +----------+--------+------+------+------+--+ | zhangsa | angsa | sa | zh | sa | | lisi | si | si | li | si | | wanger | nger | er | wa | er | | liiu | iu | iu | li | iu | | qibaqiu | baqiu | iu | qi | iu | | wangshi | ngshi | hi | wa | hi | | liwei | wei | ei | li | ei | | wutong | tong | ng | wu | ng | | lilisi | lisi | si | li | si | | qishili | shili | li | qi | li | +----------+--------+------+------+------+--+## 字符串轉大寫:upper,ucase 字符串轉小寫:lower,lcaseselect user_id,upper(user_id),ucase(user_id), lower(upper(user_id)),lcase(ucase(user_id)),lower(ucase(user_id)) from order_detail;+----------+----------+----------+----------+----------+----------+--+ | user_id | _c1 | _c2 | _c3 | _c4 | _c5 | +----------+----------+----------+----------+----------+----------+--+ | zhangsa | ZHANGSA | ZHANGSA | zhangsa | zhangsa | zhangsa | | lisi | LISI | LISI | lisi | lisi | lisi | | wanger | WANGER | WANGER | wanger | wanger | wanger | | liiu | LIIU | LIIU | liiu | liiu | liiu | | qibaqiu | QIBAQIU | QIBAQIU | qibaqiu | qibaqiu | qibaqiu | | wangshi | WANGSHI | WANGSHI | wangshi | wangshi | wangshi | | liwei | LIWEI | LIWEI | liwei | liwei | liwei | | wutong | WUTONG | WUTONG | wutong | wutong | wutong | | lilisi | LILISI | LILISI | lilisi | lilisi | lilisi | | qishili | QISHILI | QISHILI | qishili | qishili | qishili | +----------+----------+----------+----------+----------+----------+--+## 去兩邊的空格:trim 左邊去空格:ltrim 右邊去空格:rtrimselect trim(' abc '),ltrim(' abc'),rtrim('abc ') from order_detail limit 1;+------+------+------+--+ | _c0 | _c1 | _c2 | +------+------+------+--+ | abc | abc | abc | +------+------+------+--+## 正則表達式替換: regexp_replace 說明：將字符串 A 中的符合 java 正則表達式 B 的部分替換為 C。注意，在有些情況下要使用轉義字符, 類似 oracle 中的 regexp_replace 函數。## 正則表達式解析: regexp_extract 將字符串 subject 按照 pattern 正則表達式的規則拆分，返回 index 指定的字符。注意，在有些情況下要使用轉義字符，如等號要用雙豎線轉義，這是java正則表達式的規則。select user_id,regexp_replace(user_id, 'li|ng', '**'), regexp_extract(user_id,'li(.*?)(si)',1), regexp_extract(user_id,'li(.*?)(si)',2), regexp_extract(user_id,'li(.*?)(si)',0) from order_detail; +----------+----------+------+------+---------+--+ | user_id | _c1 | _c2 | _c3 | _c4 | +----------+----------+------+------+---------+--+ | zhangsa | zha**sa | | | | | lisi | **si | | si | lisi | | wanger | wa**er | | | | | liiu | **iu | | | | | qibaqiu | qibaqiu | | | | | wangshi | wa**shi | | | | | liwei | **wei | | | | | wutong | wuto** | | | | | lilisi | ****si | li | si | lilisi | | qishili | qishi** | | | | +----------+----------+------+------+---------+--+select regexp_extract('http://facebook.com/path1/p.php?k1=v1543643&k2=v3245#Ref1', '.*?k1\\=([^&]+)', 1), regexp_extract('http://facebook.com/path1/p.php?k1=v1543643&k2=v3245#Ref1', '.*?k2\\=([^#]+)', 1) from order_detail limit 1;+-----------+--------+--+ | _c0 | _c1 | +-----------+--------+--+ | v1543643 | v3245 | +-----------+--------+--+## URL解析:parse_url 語法: parse_url(string urlString, string partToExtract [, string keyToExtract]) 說明：返回 URL 中指定的部分。 partToExtract 的有效值為： HOST, PATH, QUERY, REF,PROTOCOL, AUTHORITY, FILE, and USERINFO. 舉例：select parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'HOST'), parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'PATH'), parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'QUERY'), parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'QUERY','k2'), parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'REF'), parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'PROTOCOL'), parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'AUTHORITY'), parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'FILE') from order_detail limit 1;+---------------+---------------+--------------+------+-------+-------+---------------+---------------------------+--+ | _c0 | _c1 | _c2 | _c3 | _c4 | _c5 | _c6 | _c7 | +---------------+---------------+--------------+------+-------+-------+---------------+---------------------------+--+ | facebook.com | /path1/p.php | k1=v1&k2=v2 | v2 | Ref1 | http | facebook.com | /path1/p.php?k1=v1&k2=v2 | +---------------+---------------+--------------+------+-------+-------+---------------+---------------------------+--+## json解析: get_json_object 語法: get_json_object(string json_string, string path) 說明：解析 json 的字符串 json_string,返回 path 指定的內容。如果輸入的 json 字符串無效，那么返回 NULL。select get_json_object( '{"store": {"fruit":\[{"weight":8,"type":"apple"},{"weight":9,"type":"pear"}], "bicycle":{"price":19.95,"color":"red"} }, "email":"amy@only_for_json_udf_test.net", "owner":"amy" }', '$.owner'), get_json_object( '{"store": {"fruit":\[{"weight":8,"type":"apple"},{"weight":9,"type":"pear"}], "bicycle":{"price":19.95,"color":"red"} }, "email":"amy@only_for_json_udf_test.net", "owner":"amy" }', '$.store.fruit[0].type') from order_detail limit 1;+------+--------+--+ | _c0 | _c1 | +------+--------+--+ | amy | apple | +------+--------+--+## json_tuple 語法: json_tuple(string jsonStr,string k1,string k2, ...) 參數為一組鍵k1，k2……和JSON字符串，返回值的元組。該方法比 get_json_object 高效，因為可以在一次調用中輸入多個鍵.select a.user_id, b.* from order_detail a lateral view json_tuple('{"store": {"fruit":\[{"weight":8,"type":"apple"},{"weight":9,"type":"pear"}], "bicycle":{"price":19.95,"color":"red"} }, "email":"amy@only_for_json_udf_test.net", "owner":"amy" }', 'email', 'owner') b as email, owner limit 1;+----------+---------------------------------+--------+--+ | user_id | email | owner | +----------+---------------------------------+--------+--+ | zhangsa | amy@only_for_json_udf_test.net | amy | +----------+---------------------------------+--------+--+## parse_url_tupleSELECT b.* from ( select 'http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1' as urlstr from order_detail limit 1 )a LATERAL VIEW parse_url_tuple(a.urlstr, 'HOST', 'PATH', 'QUERY', 'QUERY:k1') b as host, path, query, query_k1 LIMIT 1;+---------------+---------------+--------------+-----------+--+ | host | path | query | query_k1 | +---------------+---------------+--------------+-----------+--+ | facebook.com | /path1/p.php | k1=v1&k2=v2 | v1 | +---------------+---------------+--------------+-----------+--+空格字符串:space 重復字符串:repeat 首字符ascii:ascii select space(10), length(space(10)), repeat('abc',5), ascii('abcde') from order_detail limit 1;+-------------+------+------------------+------+--+ | _c0 | _c1 | _c2 | _c3 | +-------------+------+------------------+------+--+ | | 10 | abcabcabcabcabc | 97 | +-------------+------+------------------+------+--+左補足函數:lpad 右補足函數:rpad 語法: lpad(string str, int len, string pad) 說明：lpad將 str 進行用 pad 進行左補足到 len 位, rpad將 str 進行用 pad 進行右補足到 len 位注意：與 GP,ORACLE 不同; pad不能默認select lpad('abc',10,'td'),rpad('abc',10,'td') from order_detail limit 1;+-------------+-------------+--+ | _c0 | _c1 | +-------------+-------------+--+ | tdtdtdtabc | abctdtdtdt | +-------------+-------------+--+分割字符串函數: split集合查找函數: find_in_set 語法: find_in_set(string str, string strList) 說明: 返回 str 在 strlist 第一次出現的位置， strlist 是用逗號分割的字符串。如果沒有找該 str 字符，則返回 0select split('abtcdtef','t'), find_in_set('ab','ef,ab,de'), find_in_set('at','ef,ab,de') from order_detail limit 1; +-------------------+------+------+--+ | _c0 | _c1 | _c2 | +-------------------+------+------+--+ | ["ab","cd","ef"] | 2 | 0 | +-------------------+------+------+--+## string轉map：str_to_map 語法：str_to_map(text[, delimiter1, delimiter2]) 說明：使用兩個分隔符將文本拆分為鍵值對。 Delimiter1將文本分成K-V對，Delimiter2分割每個K-V對。對于delimiter1默認分隔符是'，'，對于delimiter2默認分隔符是':'。 select str_to_map('aaa:11&bbb:22', '&', ':') from order_detail limit 1; +--------------------------+--+ | _c0 | +--------------------------+--+ | {"bbb":"22","aaa":"11"} | +--------------------------+--+select str_to_map('aaa:11&bbb:22', '&', ':')['aaa'] from order_detail limit 1;+------+--+ | _c0 | +------+--+ | 11 | +------+--+select str_to_map('aaa:11,bbb:22') from person limit 1;{"bbb":"22","aaa":"11"}

集合統計函數

## 個數統計:count 總和統計:sum 語法: count(*), count(expr), count(DISTINCT expr[, expr_.]) 說明: count(*)統計檢索出的行的個數，包括 NULL 值的行； count(expr)返回指定字段的非空值的個數； count(DISTINCT expr[, expr_.])返回指定字段的不同的非空值的個數語法: sum(col), sum(DISTINCT col) 說明: sum(col)統計結果集中 col 的相加的結果； sum(DISTINCT col)統計結果中 col 不同值select count(*),count(user_type),count(distinct user_type), sum(sales),sum(distinct sales) from order_detail; +------+------+------+------+------+--+ | _c0 | _c1 | _c2 | _c3 | _c4 | +------+------+------+------+------+--+ | 10 | 10 | 2 | 29 | 17 | +------+------+------+------+------+--+## 平均值統計:avg 最小值統計:min 最大值統計:maxselect avg(sales),avg(distinct sales),min(sales),max(distinct sales) from order_detail;+------+------+------+------+--+ | _c0 | _c1 | _c2 | _c3 | +------+------+------+------+--+ | 2.9 | 3.4 | 1 | 6 | +------+------+------+------+--+## 標準差：stddev_samp, stddev, stddev_pop stddev_pop <==> stddev## 方差：var_samp, var_pop當我們需要真實的標準差/方差的時候最好是使用： stddev stddev_pop var_pop 而只是需要得到少量數據的標準差/方差的近似值可以選用： stddev_samp var_sampselect var_pop(sales),var_samp(sales), stddev_pop(sales),stddev(sales),stddev_samp(sales), pow(stddev_pop(sales),2),pow(stddev_samp(sales),2) from order_detail;+-------+--------------------+---------------------+---------------------+---------------------+---------------------+---------------------+--+ | _c0 | _c1 | _c2 | _c3 | _c4 | _c5 | _c6 | +-------+--------------------+---------------------+---------------------+---------------------+---------------------+---------------------+--+ | 3.09 | 3.433333333333333 | 1.7578395831246945 | 1.7578395831246945 | 1.8529256146249728 | 3.0899999999999994 | 3.4333333333333336 | +-------+--------------------+---------------------+---------------------+---------------------+---------------------+---------------------+--+## 百分位數: percentile 近似百分位數: percentile_approx 直方圖: histogram_numeric語法: percentile_approx(DOUBLE col, p [, B]) 返回值: double 說明: 求近似的第 pth 個百分位數， p 必須介于 0 和 1 之間，返回類型為 double，但是col 字段支持浮點類型。參數 B 控制內存消耗的近似精度， B越大，結果的準確度越高。默認為 10,000。當 col 字段中的 distinct 值的個數小于 B 時，結果為準確的百分位數select percentile(sales,0.2), percentile_approx(sales,0.5,10000), histogram_numeric(sales,5) from order_detail;+------+------+----------------------------------------------------------------------------------------------+--+ | _c0 | _c1 | _c2 | +------+------+----------------------------------------------------------------------------------------------+--+ | 1.0 | 2.0 | [{"x":1.0,"y":3.0},{"x":2.0,"y":2.0},{"x":3.0,"y":2.0},{"x":5.0,"y":2.0},{"x":6.0,"y":1.0}] | +------+------+----------------------------------------------------------------------------------------------+--+select inline(histogram_numeric(sales,10)) from order_detail;+------+------+--+ | x | y | +------+------+--+ | 1.0 | 3.0 | | 2.0 | 2.0 | | 3.0 | 2.0 | | 5.0 | 2.0 | | 6.0 | 1.0 | +------+------+--+### 后面可以輸入多個百分位數，返回類型也為 array<double>，其中為對應的百分位數。 select percentile(sales,array(0.2,0.4,0.6)), percentile_approx(sales,array(0.2,0.4,0.6),10000) from order_detail;+----------------+----------------+--+ | _c0 | _c1 | +----------------+----------------+--+ | [1.0,2.0,3.0] | [1.0,1.5,2.5] | +----------------+----------------+--+

復雜類型訪問操作及統計函數

測試數據集： tony 1338 hello,woddd 1,2 a1,a2,a3 k1:1.0,k2:2.0,k3:3.0 s1,s2,s3,4 mark 5453 kke,ladyg 2,3 a4,a5,a6 k4:4.0,k5:5.0,k2:6.0 s4,s5,s6,6 ivyfd 4323 aa,thq,dsx 3,6 a7,a8,a9 k7:7.0,k8:8.0,k2:9.0 s7,s8,s9,9 drop table employees; create external table if not exists employees( name string, salary string, happy_word string, happy_num array<int>, subordinates array<string>, deductions map<string,float>, address struct<street:string,city:string,state:string,zip:int> ) row format delimited fields terminated by '\t' collection items terminated by ',' map keys terminated by ':' lines terminated by '\n' stored as textfile;hdfs dfs -put /home/liguodong/data/muldata.txt /temp/lgdload data inpath '/temp/lgd/muldata.txt' overwrite into table employees;select * from employees;Getting log thread is interrupted, since query is done! +--------+---------+--------------+------------+-------------------+-------------------------------+---------------------------------------------------+--+ | name | salary | happy_word | happy_num | subordinates | deductions | address | +--------+---------+--------------+------------+-------------------+-------------------------------+---------------------------------------------------+--+ | tony | 1338 | hello,woddd | [1,2] | ["a1","a2","a3"] | {"k1":1.0,"k2":2.0,"k3":3.0} | {"street":"s1","city":"s2","state":"s3","zip":4} | | mark | 5453 | kke,ladyg | [2,3] | ["a4","a5","a6"] | {"k4":4.0,"k5":5.0,"k2":6.0} | {"street":"s4","city":"s5","state":"s6","zip":6} | | ivyfd | 4323 | aa,thq,dsx | [3,6] | ["a7","a8","a9"] | {"k7":7.0,"k8":8.0,"k2":9.0} | {"street":"s7","city":"s8","state":"s9","zip":9} | +--------+---------+--------------+------------+-------------------+-------------------------------+---------------------------------------------------+--+## 訪問數組 Map 結構體select name,salary, subordinates[1],deductions['k2'],deductions['k3'],address.city from employees; +--------+---------+------+------+-------+-------+--+ | name | salary | _c2 | _c3 | _c4 | city | +--------+---------+------+------+-------+-------+--+ | tony | 1338 | a2 | 2.0 | 3.0 | s2 | | mark | 5453 | a5 | 6.0 | NULL | s5 | | ivyfd | 4323 | a8 | 9.0 | NULL | s8 | +--------+---------+------+------+-------+-------+--+## Map類型長度 Array類型長度select size(deductions),size(subordinates) from employees limit 1;+------+------+--+ | _c0 | _c1 | +------+------+--+ | 3 | 3 | +------+------+--+## 類型轉換: castselect cast(salary as int),cast(deductions['k2'] as bigint) from employees;+---------+------+--+ | salary | _c1 | +---------+------+--+ | 1338 | 2 | | 5453 | 6 | | 4323 | 9 | +---------+------+--+### LATERAL VIEW 行轉列 SELECT name, ad_subordinate FROM employees LATERAL VIEW explode(subordinates) addTable AS ad_subordinate; +--------+-----------------+--+ | name | ad_subordinate | +--------+-----------------+--+ | tony | a1 | | tony | a2 | | tony | a3 | | mark | a4 | | mark | a5 | | mark | a6 | | ivyfd | a7 | | ivyfd | a8 | | ivyfd | a9 | +--------+-----------------+--+SELECT name, count(1) FROM employees LATERAL VIEW explode(subordinates) addTable AS ad_subordinate group by name; +--------+------+--+ | name | _c1 | +--------+------+--+ | ivyfd | 3 | | mark | 3 | | tony | 3 | +--------+------+--+SELECT ad_subordinate, ad_num FROM employees LATERAL VIEW explode(subordinates) addTable AS ad_subordinate LATERAL VIEW explode(happy_num) addTable2 AS ad_num; +-----------------+---------+--+ | ad_subordinate | ad_num | +-----------------+---------+--+ | a1 | 1 | | a1 | 2 | | a2 | 1 | | a2 | 2 | | a3 | 1 | | a3 | 2 | | a4 | 2 | | a4 | 3 | | a5 | 2 | | a5 | 3 | | a6 | 2 | | a6 | 3 | | a7 | 3 | | a7 | 6 | | a8 | 3 | | a8 | 6 | | a9 | 3 | | a9 | 6 | +-----------------+---------+--+### 多個LATERAL VIEW SELECT name, count(1) FROM employees LATERAL VIEW explode(subordinates) addTable AS ad_subordinate LATERAL VIEW explode(happy_num) addTable2 AS ad_num group by name;+--------+------+--+ | name | _c1 | +--------+------+--+ | ivyfd | 6 | | mark | 6 | | tony | 6 | +--------+------+--+### 不滿足條件產生空行 SELECT AA.name, BB.* FROM employees AA LATERAL VIEW explode(array()) BB AS a limit 10; +-------+----+--+ | name | a | +-------+----+--+ +-------+----+--+### OUTER 避免永遠不產生結果，無滿足條件的行，在該列會產生NULL值。 SELECT AA.name, BB.* FROM employees AA LATERAL VIEW OUTER explode(array()) BB AS a limit 10; +--------+-------+--+ | name | a | +--------+-------+--+ | tony | NULL | | mark | NULL | | ivyfd | NULL | +--------+-------+--+### 字符串切分成多列 SELECT name, word FROM employees LATERAL VIEW explode(split(happy_word,',')) addTable AS word;+--------+--------+--+ | name | word | +--------+--------+--+ | tony | hello | | tony | woddd | | mark | kke | | mark | ladyg | | ivyfd | aa | | ivyfd | thq | | ivyfd | dsx | +--------+--------+--+

--------------------- 本文來自李國冬的CSDN 博客，全文地址請點擊：https://blog.csdn.net/scgaliguodong123_/article/details/60881166?utm_source=copy?

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