????????Batch??????????????????????????????????I/O?????????????????????????????????????????η??????????????????????????CPU??????
????In List
????????????????????????????????????????????ID????????????ЩID??????????????????????????????????????
????????????????????ID??????????????????????
????for: var in ids[] do begin
????SELECT * FROM table_name WHERE id=:var;
????end;
????????????????????????????????????????????????????????????????????????????????ID InList??????????????????ν??????????η?????????????????
????SELECT * FROM table_name
????WHERE id IN ids[];
???????洢????
????Inceptor???洢??????????????洢?????????????????????洢????????SQL?????????????????????顣??????????????????????????????????????????????????洢?????е??????????????????????????????????????????????У??????????????洢????????У????????SQL???????????
??????????????洢?????????????????????
??????????????????????Ч???
?????????罻???д??????????SQL??????????貧???Щ???????????????????????????????????Ч???
????4. ??????????????
????CPU????SQL?л????????????????????????CPU???????????????Щ???????????????????????磬???ж?????????????????????????????????????????????????????CPU????????????????????????????????????????м??????????????????????????????????????????????????????ι滮????????????????
????????????SQL?е???????????Inceptor????????????????(??????????)?н???????????????????CPU???????????????????????????衣??LIKE????????????????CPU??????????????????????????????????????????????????????????????????御????In-List???LIKE????In-List?а???LIKE???п?????????
????????3??????????????????
????SELECT * FROM table_name
????WHERE column_name LIKE ‘%abc%’;
???????????????????????????‘cabc’??‘abce’??‘cabe’???????????????????????????
????SELECT * FROM table_name
????WHERE column_name IN (‘cabc’?? ‘abce’?? ‘cabe’);
????????4?????In-List??????????SELECT??????????????????м?С?????In?б????????????????????????????????м?????
????SELECT * FROM table_name
????WHERE column_name IN (
????SELECT col_name FROM tbl WHERE gender = ‘f’
????);
????????????????????Hadoop???г????SQL????·???????????·?????????????????????????????????????Щ?·??????????????????SQL??????????Щ???????
?????????????????Щ????·?????ó????
????1???????????ο?????μ??????????;
????2??????SELECT?????????????μ??????????;
????3????????漰????????????????????????????????????????????????;
????4????????????????????????????CPU????
????5???????????????????????????棬???????????SQL??????Hadoop?????и????????????