????16???????????????????????磬?г????????????
????select * from tab where TName='T_TEST'???
????select table_name??table_type from information_schema.tables where table_schema = 'user' and table_name=' T_TEST '
????17??MySQL??update??????б????????
????update T_TEST set Flag = 0 where field1 in
????(select distinct b.field1 from T_TEST b where b.flag=1)
????18??Oracle??’’??null??????MySQL???
????select 1 from dual where '' is null??Oracle???????????????MySQL?2???
????dual???????substr??trim????????????÷????Oracle????
???????С??????
????????????Oracle?????MySQL?????鷳????????????????????????????????????????????????????????SQL?????????????????????????????????????????????????????????Щ??????????????????????????????????????????????????????????????????ü???????????????y????????????Щ????????J2EE??Hibernate?????
??????л????Oracle???????????????????????к????MySQL??е???????????????ò??????Щ?????????????磬???cache??????????????????????ù???????????????????????????????????????ó????????????????????Щ????MySQL??У??????????????У????????????????
??????????????????MySQL??bug??????????????????????????????????????ó???????MySQL?????ò?????????????????еú?Oracle??????á?