what is explain plan?, given an example...
Answers were Sorted based on User's Feedback
Answer / shivainduja
An explain plan is a representation of the access path that
is taken when a query is executed within Oracle.
SQL> explain plan for select * from emp2;
Explained.
SQL> select * from table (DBMS_XPLAN.display);
PLAN_TABLE_OUTPUT
-------------------------------------
Plan hash value: 2941272003
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost
(%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 15 | 570 | 3
(0)| 00:00:01 |
| 1 | TABLE ACCESS FULL| EMP2 | 15 | 570 | 3
(0)| 00:00:01 |
--------------------------------------------------------------------------
8 rows selected.
Is This Answer Correct ? | 4 Yes | 1 No |
Answer / rajesh venati
this will also work.
An Explain Plan is a tool that you can use to have Oracle
explain to you how it plans on executing your query.
ex:-
SQL> set autotrace on explain
SQL> select * from emp;
Execution Plan
----------------------------------------------------------
Plan hash value: 3956160932
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost
(%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 14 | 518 | 3
(0)| 00:00:01 |
| 1 | TABLE ACCESS FULL| EMP | 14 | 518 | 3
(0)| 00:00:01 |
--------------------------------------------------------------------------
Is This Answer Correct ? | 1 Yes | 0 No |
Explain Plan determines the execution plan of SQL statement.
Is This Answer Correct ? | 0 Yes | 0 No |
how to rename an existing column in a table? : Sql dba
what is the difference between clustered and non clustered index in sql? : Sql dba
How do you write a complex sql query?
what is the difference between join and union? : Sql dba
What is difference between group by and partition by?
What is an index and types of indexes. How many number of indexes can be used per table ?
12 Answers Accenture, BirlaSoft, Cognizant, CTS, Symphony,
i hv 30 rows with date.ex:1month hav 4 weeks i want 1st day of the every week.write the qry for that.example jan has 4 weeks i need 1st dd for evry wk
What are sql built in functions?
How does sql profiler work?
types of exceptions and what is meant by pragma autonomous_transaction ?what is the use.
What is blind sql injection?
How to delete same emp id in sql query for exmaple in emp table emp id, empname, emp address. for example emp id =5, repeated in two times in rows same id how to delete same empid please any one of the write query send in my id