Monday, July 29, 2013

How to display first k rows in SQL

To display first k rows from a table make use of rownum keyword which initially has value 0 and gets incremented by one when it moves to next row.

Here is the example to display first three rows from emp table.

select *from emp where rownum < 4

Sunday, July 28, 2013

Find maximum salary in each department

we will use the table displayed below for further post unless and otherwise mentioned. table emp contains five column eno(employee number),ename(employee name),sal(employee salary),deptno(employee's department number),mgr(employee's manager number).

the below query displays name of each employee,salary and deptno who are having maximum salary in their department.

Granting and retrieving privileges in oracle

if we want to assign some privilege to some user say "sonu" then we can assign privilege using command GRANT

grant privilege_name on table_name to user_name;
if there are multiple privileges then seperate using commas.
in the figure it's assigning all privileges to user "sonu"

 similarly we can retrieve privilege using revoke command which is shown in the below figure.

Thursday, June 27, 2013

how to recover grub


To recover grub boot loader install Easy bcd you can download it from cnet

1. Once you have installed easy bcd open it

2.Go to option add new entry in left pan

3. Now click on tab linux /BSD

4. Select grub2 (which is latest grub boot loader) from type

5. Type any name say "my linux" which you want to display in menu

6. Click on Add entry, you will see message flashing in left bottom corner "my linux has been added successfully"

Now restart your system and enjoy.

> do suggest/comment

Tuesday, June 11, 2013

why should i hire you

    This is very famous HR interview question and idea behind asking this question is that they want to know your strengths. it's indirect way to ask your strength like "what are your strength". so you should tell your strengths like i am good at this and that (your technical strengths like any subjects,communication skills, fast learner etc.).

    so finally you need to tell your strengths but do not say that i am the best and you should hire me and yes do not mention so many  strengths even if you have.only tell few of them at which you are strong.

Sunday, June 9, 2013

How to install .tar.gz in ubuntu

For example you want to install vlc.tar.gz file in ubuntu then first you need to extract this .tar.gz file using the following command

$ tar -xvzf vlc.tar.gz

one folder will be created with name vlc, go to this folder  and now run these commands

$make install

if any dependency error message is shown then resolve that dependency and then run
$make install

Sunday, June 2, 2013

What is LPR command in linux

lpr command is used to give file for printing to the destined printer.
there are few options for lpr command

-P prints file to the named printer or give address of printer

-# sets number of copies to be printed between 1 to 100

for example
lpr -P addressofprinter -# 4 filename1 filename2

you can print multiple files at a time. number after -# is number of copies to be printed.