Oracle 创建 Sequence
Fitness 胸
Fitness
2008金融危机 MBS、CDO、CDS
组合索引的引导列
组合索引的列顺序如何排列
select count(*) from t1,t2 where t1.id=t2.id and t1.owner='SCOTT';
这种sql，t2上建立(id)索引，t1上建立组合索引(owner,id)
尽量把join列放到组合索引最后面
INDEX FAST FULL SCANinx_id_ownerselect count(*) from t1,t2 where t1.id=t2.id and t1.owner='SCOTT';
INDEX RANGE SCANinx_owner_idselect count(*) from t1,t2 where t1.id=t2.id and t1.owner='SCOTT';
INDEX FULL SCANinx_id_ownerselect /*+ index(t1 inx_id_owner) */ count(*) from t1,t2 where t1.id=t2.id and t1.owner='SYS';
INDEX SKIP SCANinx_id_ownerselect /*+ index_ss(t1 inx_id_owner) */ count(*) from t1,t2 where t1.id=t2.id and t1.owner = 'SYS';