2016-11-22Subquery: Scalar subquery inline Views (in-line view) semi-join/reverse-connect scalar subquery Select followed by subquery similar to custom function can overwrite inline view with window function (In-line view) from followed by subquery similar to Design view subquery sub Query It's garbage design. A semi-connection is a subquery that has a in/exists in the back of where it is followed by a subquery with not in/not exists
NOTE: Null values are not available for columns returned by an anti-join subquery
SQL three segment splitting method
The Select section focuses on the scalar subquery custom function from the back of the focus on whether there is no inline view there is no view merge where condition part see there is no in/not in,exists/not EXISTS subquery There is no outer join there is no function on the column Causes the index to not go
Sql_trace
Alter session Set Sql_trace = true; ALTER DATABASE Set sql_trace = true; Alter session Set Tracefile_identifier = ' Test_trace '; oracle11g trace File default path: $ORACLE _base/diag/rdbms/orcl/orcl/trace
Oracle Tuning Notes
