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1Ð޸Ļù±¾±í
 Ìí¼ÓÁÐ alter table tableName add<ÐÂÁÐÃû><Êý¾ÝÀàÐÍ>[ÍêÕûÐÔÔ¼Êø]
 É¾³ýÁÐ alter table tableName drop<ÐÂÁÐÃû><Êý¾ÝÀàÐÍ>[ÍêÕûÐÔÔ¼Êø]
2´´½¨
  ½¨±ícreate table tableName(
id primary key AUTO_INCREMENT(mysql);
id primary key identity(1,1)(sql server)
)
   ½¨Á¢Ë÷Òý
  create index OID_IDX on ±íÃû(number);
  create unique index oin_idx on ±íÃû(number);´´½¨Î¨Ò»Ë÷Òý
3 É¾³ý
   É¾³ýË÷Òý drop index <Ë÷ÒýÃû>
   ɾ³ý±í     drop table <±íÃû>
4 sql¹¦ÄÜ
   Êý¾Ý²éѯ select
   Êý¾Ý¶¨Òå create drop alter
   Êý¾Ý²Ù¿Ø insert update delete
   Êý¾Ý¿ØÖÆ grant(ÊÚȨ) revoke(ÊÕ»ØȨÏÞ)
(1) Êý¾Ý²éѯ
     select * from tableName where <Ìõ¼þ±í´ïʽ> group by<ÁÐÃû>[having<Ìõ¼þ>]  order by<ÁÐÃû>[ASC DESC] 
     select distinct Sno from sc ²éѯÊý¾ÝÈ¥µôÖظ´ÐÐ
     ³£¼ûµÄ²éѯÌõ¼þ
     ±È½Ï = ,>,<,<=,<=,!=,<>,!<,!>,
     È·¶¨·¶Î§ between and |not between and
     È·¶¨¼¯ºÏ in ,not in
     ×Ö·ûÆ¥Åä like ,not like like '<Æ¥Åä·û>' Æ¥Åä·û¿ÉÒÔ°üº¬Í¨Åä·û%ºÍ_
     ¿ÕÖµ       is null ,is not null
     ¶àÖØÌõ¼þ(Âß¼­ÔËËã) and,or,not
     select  a.name,a.mialbox from a where EXISTS(select b.name from b where a.name=b.name)
     Áª½Ó²éѯjoin
     select a.number,a,name,b.age,b.sort from a join b on a.number=b.number
     inner join ÄÚÁª½Ó ÓÃÓÚ·µ»ØÁ½¸ö±íÖÐÒª²éѯµÄÁÐÊý¾Ý left join right join
     ³£¼ûÔËËãÒÔ¼°¾Û¼¯º¯Êý
         ABS(x)·µ»Ø¾ø¶ÔÖµ
   &