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SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

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 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A
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vi Editor Top Commands for Ubuntu OS

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I have given VI editor commands to use in Ubuntu operating system. You can practice using them for your benefit and you can complete your work quickly.

Ubuntu vi editor commands

To begin changing or adding to text with vi, you can enter Insert or Replace modes, as shown in the following list. When you enter Insert or Replace mode, the characters you type will appear in the text document (as opposed to being interpreted as commands). 

vi filename

This is the first command to enter into editor mode. Once you enter into editor mode, you need to enter other commands to complete your editing work.

Press the Esc key to exit to Normal mode after you are done inserting or replacing text.

List of VI Editor Commands..

i—Typed text appears before current character.
a—Typed text appears after current character.
o—Open a new line below current line to begin typing.
s—Erase current character and replace with new text.
c?—Replace ? with l, w, $, or c to change the current letter, word, end of line, or line.
r—Replace current character with the next one you type.
Shift+i—Typed text appears at the beginning of current line.
Shift+a—Typed text appears at the end of current line.
Shift+o—Open a new line above current line to begin typing.
Shift+s—Erase current line and enter new text.
Shift+c—Erase from cursor to end of line and enter new text.
Shift+r—Overwrite as you type from current character going forward.

Shortcut keys to delete or paste


x—Delete text under cursor.
d?—Replace ? with l, w, $, or d to cut the current letter, word, or end of line from cursor or entire line.
y?—Replace ? with l, w, or $ to copy (yank) the current letter, word, or end of line from cursor.
p—Pastes cut or yanked text after cursor.
Shift+x—Delete text to left of cursor.
Shift+d—Cut from cursor to end of line.
Shift+y—Yank current line .
Shift+p—Pastes cut or yanked text before cursor.

How to Save VI editor changes...

Press - Esc key
:x
Press Enter
Your work will be saved.


Summary

The above commands useful to work with VI editor. You can complete your task quickly and saves lot of time.

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