what is explain plan?, given an example...
Answer Posted / 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 |
Post New Answer View All Answers
What are stored procedures in mysql?
List out the acid properties and explain?
What are the indexing methods?
What is a primary key? Explain
what is user defined functions? : Sql dba
What does (*) mean in sql?
What is sql deadlock?
If the application is running very slow? At what points you need to go about the database in order to improve the performance?
What is date functions?
What is the command used to fetch the first 5 characters of a string?
How do you create a unique index?
Table1: Col1 col2 1 2 10 3 4 89 5 6 Table:2 Col1 col2 3 2 9 5 4 7 6 87 With the help of table1 and table2 write a query to simulate the fallowing results. Output1: Col1 col2 1 2 2 3 3 4 4 5 5 6 Output2: Col1 col2 2 3 10 4 5 89 6 7 1.Write query for single row to multiple row using sql statements. Eg:a,b,c,d,e,f Change to A B C D E F 2. Write query for multiple row to single row using sql statements. Eg2 A B C D E F Change to Eg:a,b,c,d,e,f Table1: Col1 col2 8 5 2 9 4 2 5 1.Write a query to select all the rows from a table1,if the value of A is null then corresponding B’s value should be printed in A’s value.if the value of A is null in that table then corresponding B’s value should be printed as 30. 2. write a query to find the sum of A and B .display the max among both. 3.write a query to find total number of rows from table 1. Note: if any column value is null in a row then that row should be considered as 2 rows. 4.write a query to display all the records of table1 except A containg 2 as well B containg 5. 5.rewrite the fallowing without using join and group by. Select b.title,max(bc.returneddate –bc.checkoutdate)” mostdaysout” From bookshelf_checkout bc, Book shelf B Where bc.title(+)=b.title Group by b.title. 6.rewrite fallowing query Select id_category from category_master X where exists (select 1 from sub_category Y where X.id_category=Y.id_category) Customer: Name phone1 phone2 phone3 bitwise A 23456 67890 12345 --- B 67459 89760 37689 --- Don’t_call Col1 67890 37689 1.q) update the customer table of bitwise with 1 or 0. Exists in don’t_call table menas show -1 Other wise -0. Output. Name bitwise A 010 B 010
What is vector point function?
How many sql are there?
What does := mean in pl sql?