Oracle hint

select /*+ full(t1) */ * from t1;--全表扫描
select /*+ index(t1 idx_name) */ * from t1 where object_id>2;使用指定索引
select /*+ no_index(t1 idx_name) */ * from t1 where object_id>2; --不使用指定索引
select /*+ index_desc(t1 idx_name) */ * from t1 where object_id=2; --按索引降序顺序访问数据
select /*+ index_combine(t1 idx_name) */ * from t1;--选择位图索引
select /*+ index_ffs(t1 idx_name) */ from t1 where object_id <100; --索引快速全表扫描（把索引当作一个表看待）
select /*+ index_join(t1 idx_name1 idx_name2) */ * from t1 where object_id=5 and status='VALID'; --同时使用条件列上的相关索引
select /*+ index_ss(t1 index_name) */ * from t1 where object_id=99; --跳跃式扫描
select /*+ leading(t1,t) */ t.* from t,t1 where t1.object_id=t.object_id; --指定t1为驱动作，优化器先访问此表
select /*+ ordered */ t.* from t,t1 where t1.id=t.id; --指定按from 后面表的顺序选择驱表，t作为驱动表
select /*+ use_nl(t1,t) */ t.* from t1,t where t1.object_id=t.object_id;--使用NEST LOOP表连接，适合含有小表数据关联，如一大一小(有别名，必须用别名)
select /*+ use_hash(t1,t) */ t.* from t1,t where t1.object_id=t.object_id;--使用HASH表连接，适合两个大表关联
select /*+ use_merge(t1,t) */t.* from t1,t where t1.object_id=t.object_id;--使用合并排序表连接
select /*+ no_use_nl(t1,t) */ t.* from t1,t where t1.object_id=t.object_id; --不使用NEST LOOP表连接
select /*+ no_use_hash(t1,t) */ t.* from t1,t where t1.object_id=t.object_id;--不使用HASH表连接
select /*+ no_use_merge(t1,t) */t.* from t1,t where t1.object_id=t.object_id; --不使用合并排序表连接
/*+OPTIMIZER_FEATURES_ENABLE('10.2.0.4')*/
SELECT /*+ PUSH_PRED (v1) */ t1.c1,v1.c1