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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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Relative Vs. Absolute Path in Linux: Top Differences

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 Here's the difference between the relative and absolute paths in Linux. Many a time, the programmer needs to trade in these paths. Here're simple ideas on how you can differentiate.

Top differences between absolute and relative paths

Absolute Vs. Relative path


These are the differences between Absolute and Relative path in Linux.

Absolute Path


$ cd /usr/lib

$ cd /usr/lib pwd

See this path (linux#1/usr/lib), when you give PWD, it gives a full path from the root level. This is called absolute or full path.

Think of the absolute pathname as being the complete mailing address for a package that the postal service will deliver to your next-door neighbor.

Relative Path


$ cd usr
$ /user cd lib
$ /usr/lib pwd

$ linux#1/usr/lib ==> Going step by step and achieving.

$ linux#1/usr/lib cd ../../ ==> This is the method of going back step by step.

$ linux#1 ==> This is root level directory

You are currently in the lib directory. So relative path nothing but complete information of all the mother directories.

Here, for lib, the usr is the mother directory. In simple terms, it is a step-by-step way and to reach your target directory. You might aware the .. (double dots), means you'll go to the mother of the current directory.

Think of the relative directory name as giving the postal carrier directions from your house to the one next door so that the carrier can deliver the package.

Command to got to Home directory


$ linux#1/usr/lib

You currently in the 'lib' directory.

$ cd

$ linux#1 ==> This is your home directory.

Notes: If you give cd without any arguments, it goes to home directory.

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