Oracle PL/SQL/SQL Plus/explain plan

Execution plan for the specified statement_id

    

SQL>
SQL> UNDEFINE v_statement_id;
SQL>
SQL> SELECT id ||
  2    DECODE(id, 0, "", LPAD(" ", 2*(level - 1))) || " " ||
  3    operation || " " ||
  4    options || " " ||
  5    object_name || " " ||
  6    object_type || " " ||
  7    DECODE(cost, NULL, "", "Cost = " || position)
  8  AS execution_plan
  9  FROM plan_table
 10  CONNECT BY PRIOR id = parent_id
 11  AND statement_id = "&&v_statement_id"
 12  START WITH id = 0
 13  AND statement_id = "&v_statement_id";
Enter value for v_statement_id:
old  11: AND statement_id = "&&v_statement_id"
new  11: AND statement_id = ""
old  13: AND statement_id = "&v_statement_id"
new  13: AND statement_id = ""
no rows selected
SQL>

explain plan for query

   
SQL>
SQL> create table emp(
  2           emp_id            integer         primary key
  3          ,lastname               varchar2(20)    not null
  4          ,firstname              varchar2(15)    not null
  5          ,midinit                varchar2(1)
  6          ,street                 varchar2(30)
  7          ,city                   varchar2(20)
  8          ,state                  varchar2(2)
  9          ,zip                    varchar2(5)
 10          ,shortZipCode           varchar2(4)
 11          ,area_code              varchar2(3)
 12          ,phone                  varchar2(8)
 13          ,company_name           varchar2(50));
Table created.
SQL>
SQL>
SQL> insert into emp(emp_id,lastname,firstname,midinit,street,city,state,zip,shortZipCode,area_code,phone,company_name)values
  2                      (1,"Jones","Joe","J","1 Ave","New York","NY","11202","1111","212", "221-4333","Big Company");
1 row created.
SQL> insert into emp(emp_id,lastname,firstname,midinit,street,city,state,zip,shortZipCode,area_code,phone,company_name)values
  2                      (2,"Smith","Sue","J","1 Street","New York","NY","11444","1111","212", "436-6773","Little Company");
1 row created.
SQL> insert into emp(emp_id,lastname,firstname,midinit,street,city,state,zip,shortZipCode,area_code,phone,company_name)values
  2                      (3,"X","Peggy","J","1 Drive","New York","NY","45502","2222","212", "234-4444","Medium Company");
1 row created.

SQL> explain plan for
  2  select *
  3  from emp
  4  where lastname = "Young";
Explained.
SQL> select operation
  2  from plan_table;
SELECT STATEMENT
TABLE ACCESS
SELECT STATEMENT
TABLE ACCESS
SELECT STATEMENT
TABLE ACCESS
6 rows selected.
SQL> explain plan for
  2  select *
  3  from emp
  4  where firstname="Joe";
Explained.
SQL> select operation
  2  from plan_table;
SELECT STATEMENT
TABLE ACCESS
SELECT STATEMENT
TABLE ACCESS
SELECT STATEMENT
TABLE ACCESS
SELECT STATEMENT
TABLE ACCESS
8 rows selected.
SQL>
SQL>
SQL> set autotrace off
SQL>
SQL> drop table emp;
Table dropped.
SQL>
SQL>

explain plan for select statement

   

SQL> create table t as select mod(object_id,10) id, a.* from all_objects a;
SQL>
SQL> analyze table t compute statistics
  2  for table
  3  for columns id;
SQL>
SQL>
SQL>
SQL> alter session set optimizer_max_permutations=80000;
SQL>
SQL> explain plan for
  2  select count(*)
  3    from t t1, t t2, t t3, t t4, t t5, t t6
  4   where t1.id = t2.id
  5     and t1.id = t3.id
  6     and t1.id = t4.id
  7     and t1.id = t5.id
  8     and t1.id = t6.id;
SQL>
SQL> set autotrace off
SQL>
SQL>
SQL> drop table t;

Explain sql statement

   
SQL>
SQL> create table emp (
  2      EmpNo          NUMBER(10) primary key,
  3      Name           VARCHAR2(40),
  4      DeptNo         NUMBER(2),
  5      Salary         NUMBER(7,2),
  6      Birth_Date     DATE,
  7      Soc_Sec_Num    VARCHAR2(9),
  8      State_Code     CHAR(2)
  9  );
SQL>
SQL> explain plan
  2  set Statement_Id = "TEST"
  3  for
  4  select * from emp;
SQL>
SQL> select LPAD(" ",2*Level)||Operation||" "||Options||" "||Object_Name Q_Plan
  2  from PLAN_TABLE
  3  where Statement_Id = "TEST"
  4  connect by prior ID = Parent_ID and Statement_ID = "TEST"
  5  start with ID=0;
                                                              
Q_PLAN
------------------------------------------------------------------------------------------------------------------------
  SELECT STATEMENT
    TABLE ACCESS FULL EMP
    TABLE ACCESS FULL EMP
  SELECT STATEMENT
    TABLE ACCESS FULL EMP
    TABLE ACCESS FULL EMP
                    
SQL>
SQL> set autotrace off  explain
SQL>
SQL>
SQL> drop table emp;