For Example:
Table A?have?12(?8+4) entries,?8 entries have?valid?relation?with?B
Table B?have?80(77+3) entries ,?77 entries?have?valid?relation?with?A.
then the return amount of join is :
cross?join?:?12*80
inner?join?:?77
full?outer?join?:?77+4+3
left?outer?join:?77?+?4
right?outrer?join:?77?+?3
INNER?Join ?code?as?the?following:
Select?*?from?A?a,?B?b?where?a.categoryID?=?b.categoryID;
equals:
Select?*?from?A?a?inner?join?B?b?on?a.categoryID?=?b.categoryID;
OUTER?Join ?code?as?the?following
select?*?from?A?a?full(left/right)?outer??join?B?b? on?a on?a.categoryID?=?b.categoryID;
left/right outer join claus specific ?for MSSQL:
Select?*?from?A?a,?B?b?where?a.categoryID? *=??? bcategoryID;
elect?*?from?A?a,?B?b?where?a.categoryID????? =*???b.categoryID;
left/right outer join claus specific for Oracle :
Select?*?from?A?a,?B?b?where?a.categoryID??? ?? =?? b.categoryID(+);
Select?*?from?A?a,?B?b?where?a.categoryID (+)?=??b.categoryID;
Good Resources:
http://www.w3schools.com/sql/sql_join.asp
http://www.techonthenet.com/sql/joins.htm
Table A?have?12(?8+4) entries,?8 entries have?valid?relation?with?B
Table B?have?80(77+3) entries ,?77 entries?have?valid?relation?with?A.
then the return amount of join is :
cross?join?:?12*80
inner?join?:?77
full?outer?join?:?77+4+3
left?outer?join:?77?+?4
right?outrer?join:?77?+?3
INNER?Join ?code?as?the?following:
Select?*?from?A?a,?B?b?where?a.categoryID?=?b.categoryID;
equals:
Select?*?from?A?a?inner?join?B?b?on?a.categoryID?=?b.categoryID;
OUTER?Join ?code?as?the?following
select?*?from?A?a?full(left/right)?outer??join?B?b? on?a on?a.categoryID?=?b.categoryID;
left/right outer join claus specific ?for MSSQL:
Select?*?from?A?a,?B?b?where?a.categoryID? *=??? bcategoryID;
elect?*?from?A?a,?B?b?where?a.categoryID????? =*???b.categoryID;
left/right outer join claus specific for Oracle :
Select?*?from?A?a,?B?b?where?a.categoryID??? ?? =?? b.categoryID(+);
Select?*?from?A?a,?B?b?where?a.categoryID (+)?=??b.categoryID;
Good Resources:
http://www.w3schools.com/sql/sql_join.asp
http://www.techonthenet.com/sql/joins.htm
更多文章、技術交流、商務合作、聯系博主
微信掃碼或搜索：z360901061
微信掃一掃加我為好友
QQ號聯系： 360901061
您的支持是博主寫作最大的動力，如果您喜歡我的文章，感覺我的文章對您有幫助，請用微信掃描下面二維碼支持博主2元、5元、10元、20元等您想捐的金額吧，狠狠點擊下面給點支持吧，站長非常感激您！手機微信長按不能支付解決辦法：請將微信支付二維碼保存到相冊，切換到微信，然后點擊微信右上角掃一掃功能，選擇支付二維碼完成支付。
【本文對您有幫助就好】元
