2019獨角獸企業重金招聘Python工程師標準>>>

1。正則表達式

搜索多個關鍵詞，“或”, 等同 %上海% | %內蒙古%

SELECT?*?FROM?analysis_result?WHERE?result?REGEXP?'上海|內蒙古'?LIMIT?1;

"且"

SELECT?*?FROM?analysis_result?WHERE?id?=?1?AND?result?REGEXP?'上海'?AND?result?REGEXP?'云南'?LIMIT?1; SELECT?*?FROM?analysis_result?WHERE?id?=?1?AND?result?LIKE?'%上海%'?AND?result?LIKE?'%云南%'?LIMIT?1;

2.替換字符串

將"3G"替換成"MOBILE"

UPDATE?analysis_result?SET?result=replace(result,'3G','MOBILE')?WHERE?result_type?=?'PCNUM'；

3.betweeen and 與 >= ，決不能等同于 in

select?count(1)?from?default.user?where?univname?REGEXP?'上海'?and?univyear?between?2011?and?2013;select?count(1)?from?default.user?where?univname?REGEXP?'上海'?and?univyear?>=?2011?and??univyear?<=?2013; 不同于下面 select?count(1)?from?default.user?where?univname?REGEXP?'上海'?and?univyear?in?(2010,?2013);

4.Group by 問題：Expression Not In Group By Key

select?a.collegename,?a.allcount?from?(select?collegename,?count(id)?as?allcount?from?default.user?where?collegename?!=?'\N'?group?by?collegename)?a?sort?by?a.allcount?DESC

5.數據顯示 \N 的值，需要用 = '\\N' 去查詢，非的時候就用 != '\N'

INSERT?OVERWRITE?LOCAL?DIRECTORY??'/tmp/result.txt'?select?id,name?from?t_test;

hive?-e?"select?count(id),?friendcount?from?default.user?where?id?>?0?and?birthday?!=?'\\N'?group?by?friendcount"??>?friendcount.txt hive?-e?"select?*?from?default.user?where?id?>?0?and?birthday?!=?'\\N'?group?by?friendcount?limit?10000"?>?user.txt

需要特別指出的是，在篩選某些時間字段的時候，\N仍會被篩選進來

如下面會把 \N曬進來

select?*?from?user?where?regtime?>?'2014-01-01'?limit?10

所以應該

select?*?from?user?where?regtime?!=?'\\N'?and?regtime?>?'2014-01-01'?limit?10;

6.分組后排序

select?a.univname,?a.allcount?from?(select?univname,?count(id)?as?allcount?from?default.user?where?univname?!=?'\N'?group?by?univname)?a?sort?by?a.allcount?DESC

轉載于:https://my.oschina.net/kingdelee/blog/309513

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