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1、學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http://www.edu#/free/java?pid=4函數(shù)分類HIVECLI命令顯示當(dāng)前會話有多少函數(shù)可用?SHOWFUNCTIONS;顯示函數(shù)的描述信息?DESCFUNCTIONconcat;顯示函數(shù)的擴(kuò)展描述信息?DESCFUNCTIONEXTENDEDconcat;簡單函數(shù)學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http://www.edu#/free/java?pid=4函數(shù)的計(jì)算粒度為單條記錄。?關(guān)系運(yùn)算?數(shù)學(xué)運(yùn)算?邏輯運(yùn)算?數(shù)值計(jì)算?類型轉(zhuǎn)換?日期函數(shù)?條件函數(shù)?
2、字符串函數(shù)?統(tǒng)計(jì)函數(shù)聚合函數(shù)函數(shù)處理的數(shù)據(jù)粒度為多條記錄。?sum()—求和?count()—求數(shù)據(jù)量?avg()—求平均直?distinct—求不同值數(shù)?min—求最小值?max—求最人值集合函數(shù)復(fù)合類型構(gòu)建?復(fù)雜類型訪問?復(fù)雜類型長度特殊函數(shù)窗口函數(shù)學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http://www.edu#/free/java?pid=4應(yīng)用場景?用于分區(qū)排序?動態(tài)GroupBy?TopN?累計(jì)計(jì)算?層次查詢WindowingfunctionsleadlagFIRST_VALUELAST_VALUE分析函數(shù)An
3、alyticsfunctionsRANKROW_NUMBERDENSE_RANKCUME_DISTPERCENT_RANKNTILE混合函數(shù)學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http://www.edu#/free/java?pid=4java_method(class,method[,arg1[,arg2])reflect(class,method[,arg1[,arg2..]])hash(a1[,a2...])UDTFlateralView:LATERALVIEWudtf(expression)tableAliasA
4、ScolumnAlias(‘,‘columnAlias)*fromClause:FROMbaseTable(lateralView)*ateralview用于和split,explode等UDTF一起使用,它能夠?qū)⒁恍袛?shù)據(jù)拆成多行數(shù)據(jù),在此基礎(chǔ)上可以對拆分后的數(shù)據(jù)進(jìn)行聚合。lateralview首先為原始表的每行調(diào)用UDTF,UTDF會把一行拆分成一或者多行,lateralview再把結(jié)果組合,產(chǎn)生一個支持別名表的虛擬表。常用函數(shù)Demo:createtableemployee(idstring,moneydouble,types
5、tring)rowformatdelimitedfieldsterminatedby‘t‘linesterminatedby‘‘storedastextfile;loaddatalocalinpath‘/liguodong/hive/data‘intotableemployee;select*fromemployee;優(yōu)先級依次為NOTANDORselectid,moneyfromemployeewhere(id=‘1001‘orid=‘1002‘)andmoney=‘100‘;學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http:/
6、/www.edu#/free/java?pid=4cast類型轉(zhuǎn)換selectcast(1.5asint);學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http://www.edu#/free/java?pid=4if判斷if(con,‘‘,‘‘);hive(default)>selectif(2>1,‘YES‘,‘NO‘);YEScasewhenconthen‘‘whenconthen‘‘else‘‘end(‘‘里面類型要一樣)學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http://www.edu#/free/jav
7、a?pid=4selectcasewhenid=‘1001‘then‘v1001‘whenid=‘1002‘then‘v1002‘else‘v1003‘endfromemployee;get_json_objectget_json_object(json解析函數(shù),用來處理json,必須是json格式)selectget_json_object(‘{"name":"jack","age":"20"}‘,‘$.name‘);URL解析函數(shù)parse_url(stringurlString,stringpartToExtract[,st
8、ringkeyToExtract])selectparse_url(‘http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1‘,‘HOST‘)from學(xué)大數(shù)據(jù),上小牛學(xué)堂課程視頻地址:http://www.