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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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2 Tricky Examples Python List Comprehension

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Here are the tricky examples of list comprehension. These examples useful for your project and interviews as well.

1. Printing odd numbers

Printing odd numbers

Reminder checking logic used here. If it is not equal to zero when you divide the number with 2, it treats the input number as odd and prints it.


lst1 = [x for x in range(40) if x % 2 != 0]
print('First 20 Odd Numbers:')
print(lst1)

2. Printing even numbers

Printing even numbers

Reminder checking logic used here. If it is equal to zero when you divide the number with 2, it treats the input number as even and prints it.

lst2 = [x for x in range(40) if x % 2 == 0]
print('First 20 Even Numbers:')
print(lst2)


Output from the Python scripts

First 20 Odd Numbers: 
[1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39]


First 20 Even Numbers: 
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38] 


** Process exited - Return Code: 0
** Press Enter to exit terminal

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