A
substitution variable is special type of variable which is automatic declare
and automatic destroyed in the system itself advantage of S.V is
It
makes a statement dynamic as because it is declare automatically it can able to
store any type of data in run time S.V in 2 diff categories
1.
Statement type
2.
Session type
Statement type
It is type of variable which is
automatically declares whenever a statement strat exaction and automatically
destroyed once the statement is exacted this type of variable is fail by (&)
Ex
- &dno
Session
type
On
other hand where type of variable is a variable once declare and declare with a
value will return the value unless until exit of *plus and variable is
explicitly destroyed this type of denoted by (&&)
Ex
- &&dno
Sql>
set verify off
Sql>select
ename, job, depptno from emp
Where
deptno=&deptno;
Note
:
Set verify off – it is a sql
*plus comment respond able sures the verification message
Select
ename, job, deptno from emp where job=’&job’;
The
above example are the example of statement type
Select
empno, deptno from emp
Where
dept no= ‘&&deptno’;
Above
ex is session type
NOTE:
Define
and Undefined are two sql*plus commands reasonable to control session variable.
Sql>undefined
dno;
Above
command will destroy substation variable
Sql>define
dno=0
Above
command is used reassign a substation variable
Reporting through select statement:
Reporting
is a concept through which data will represent in customize manner through
query statement. The command mains for reporting as basically sql*plus Command.
Sql>column ename heading name
Sql>column
sal heading salary
Above
ex are required to provide session type allow
Sql>column
sal heading salary format ‘$99.999’;
Sql>column
comm. format ‘$99.999’, nul ‘no comm’
Sql>column
sal clear
It
is used for clear the one column
Sql>clear
column
Above
sql command used for clear all column without exit sql command
Working
with T-TITLE and B-TITLE
Sql>TTITLE
‘report for 2008/2009’;
Sql>BTITLE
’THANK U’;
One
ttitle and btitle insert it aplyable for any table in oracle table;
Any
table in oracle table to sub press
Sql
> TTITLE OFF
SQL>
BTITLE OFF
