Monday, 17 September 2012

Is there any function in oracle to check whether a value is numeric or not. I have a column which contains both numeric and alphanumeric data. I want to fetch only the numeric data from that column. Can anyone tell me how to do it?


There does not exists any build in function which checks for a numeric value instead you can write your own function as follows.

CREATE OR REPLACE FUNCTION Isnumber(p_num VARCHAR2) RETURN NUMBER
AS
 a NUMBER;
BEGIN
 a := p_num;
 RETURN 1;
EXCEPTION WHEN OTHERS THEN
 RETURN 0;
END;
/


This function can now be called in a SQL query which will retum 1 if the value passwd is numeric else it will return 0.

OR

select * from test where translate(a,'_0123456789','_') is null;
=====================================
Check Constraint
--------------------
ALTER TABLE suppliers
add CONSTRAINT check_supplier_name
   CHECK (supplier_name IN ('IBM', 'Microsoft', 'Nvidia'));

How to see the Difference between two table coulmns:-
========================================================
scott@ORA817.US.ORACLE.COM> create table t1 as select * from emp where 1=0;

Table created.

scott@ORA817.US.ORACLE.COM> create table t2 as select * from t1;

Table created.

scott@ORA817.US.ORACLE.COM>
scott@ORA817.US.ORACLE.COM> alter table t2 drop column ename;

Table altered.

scott@ORA817.US.ORACLE.COM> alter table t2 modify job varchar2(10);

Table altered.

scott@ORA817.US.ORACLE.COM>
scott@ORA817.US.ORACLE.COM> column data_type format a10
scott@ORA817.US.ORACLE.COM> (
  2  select 'IN T1, NOT T2', column_name,data_type,data_length
  3    from user_tab_columns
  4   where table_name = 'T1'
  5  MINUS
  6  select 'IN T1, NOT T2', column_name,data_type,data_length
  7    from user_tab_columns
  8   where table_name = 'T2'
  9  )
 10  UNION ALL
 11  (
 12  select 'IN T2, NOT T1', column_name,data_type,data_length
 13    from user_tab_columns
 14   where table_name = 'T2'
 15  MINUS
 16  select 'IN T2, NOT T1', column_name,data_type,data_length
 17    from user_tab_columns
 18   where table_name = 'T1'
 19  )
 20  /

'INT1,NOTT2'  COLUMN_NAME                    DATA_TYPE  DATA_LENGTH
------------- ------------------------------ ---------- -----------
IN T1, NOT T2 ENAME                          VARCHAR2            10
IN T1, NOT T2 JOB                            VARCHAR2             9
IN T2, NOT T1 JOB                            VARCHAR2            10

scott@ORA817.US.ORACLE.COM>
===============================================================
20)How to find out department wise second maximum salary.

select distinct d1.deptno, e1.sal

from emp e1, dept d1

where 2 = (select count(distinct e2.sal)

                       from emp e2, dept d2

                    where e2.sal >= e1.sal

                        and d2.deptno = e2.deptno

                        and d1.deptno = d2.deptno)

and d1.deptno = e1.deptno
=================================
21) In a cursor going we have 10 records now i want go to exactly for only 5th record.is it possible??
Ans:-
      Yes, It is possible u can use the rowcount after fethchin
Declare
  cursor cur_t is select * from t4;
  rec_t t4%rowtype;
  i number(2);
begin
  open cur_t;
   for i in 1..10
   LOOP
      fetch cur_t into rec_t;
      if cur_t%rowcount in (5) --or IF i in(5) also we can use
      then
      dbms_output.put_line('no: ' || rec_t.no || ', name: ' || rec_t.name);    
      end if;
   end loop;
end;
=======================================================
Mutating table Example:-
-----------------

Example 1

Select in a mutating table from a row trigger (Tested on Oracle 8.1.7)

We want to explain this situation on an example. We have two tables "A" and "B". "A" is the master table and "B" the detail table. We specified a foreign key between "B" and "A" with the CASCADE DELETE option.



Here are the CREATE statements

drop table B;
drop table A;

create table A (
  ida    number   not null,
  vala   varchar2(10),
  primary key(ida));

create table B (
  idb    number,
  valb   varchar2(10),
  foreign key (idb) references A (ida) on delete cascade)
/

create or replace trigger b_br
after delete on B
for each row
declare
    n integer;
begin
  select count(*) into n from A;
  dbms_output.put_line('there are ' || n || ' rows in A');
  dbms_output.put_line('after statment on B');
  dbms_output.new_line;
end;
/

insert into A values(1,'Table A');
insert into A values(2,'Table A');
insert into B values(1,'Table B');
insert into B values(1,'Table B');
commit;

set serveroutput on;
delete from A where idA = 1;

ERROR at line 1:
ORA-04091: table SCOTT.A is mutating, trigger/function may not see
ORA-06512: at "SCOTT.B_BR", line 4
ORA-04088: error during execution of trigger 'SCOTT.B_BR'

1) Retrive the last 10 rows from a table

select rownum from emp
group by rownum
having rownum >=(select max(rownum)-10 from emp)
(or)
select * from (select rownum a, CLASS_CODE,CLASS_DESC from clm)
where a > ( select (max(rownum)-10) from clm)

2) How to Retrive the Duplicate rows from a table

SELECT , COUNT(*) FROM TABLE.NAME  
GROUP BY                              
HAVING COUNT(*) > 1        

3) Department wise 2nd heighest Salary

select distinct d1.deptno, e1.sal
from emp e1, dept d1
where 2 = (select count(distinct e2.sal)
                       from emp e2, dept d2
                       where e2.sal >= e1.sal
                       and d2.deptno = e2.deptno
                       and d1.deptno = d2.deptno)
and d1.deptno = e1.deptno
===================================================
Select  max(e1.sal),e1.deptno
from emp e1
where sal <=(select max(sal)
             from emp e2
             where  e2.deptno = e1.deptno)
group by  e1.deptno

Hewitt Associates(26-JUN-07):-
==============================

1)To get the balance based on DRCR

 select SUM(DECODE(DRCR,'C',amount,0))-SUM(DECODE(DRCR,'D',amount,0)) from account

2)
     Column
     =========
3
2
1
A001
A002
A003
1001
1002
1003

Using the Order by Whats the Order will come

Answer is
SNO -->VARCHAR2 field
----
1
1000
1001
2
3
A001
A002
A003
a004
a200

It will Give the Assending/desending Order Based on Ascii Value...

Inline View:-
===============

SELECT ename,deptno
FROM (SELECT ename,deptno
      FROM emp)a
     (SELECT deptno
      FROM emp)b
WHERE a.deptno = b.deptno

--->select sal,sum(sal) over (order by sal) TOTALSALARY from salary;
       SAL TOTALSALARY
---------- -----------
      1000        1000
      2000        3000
      3000        6000
      4000       10000

No comments:

Post a Comment