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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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Python Abstract Classes to Learn Quickly

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Here's the best example of how to understand the abstract classes of python quickly. An abstract class means it is a skeleton. You cannot instantiate abstract classes.

For Example:

The abstract class name is 'dog'

o = dog()

It gives an error. Since the 'dog' is an abstract class.

I am sharing with you a clear understanding of abstract class. So that you can tell confidently about these classes.

Here is the beautiful answer with syntax and examples of the Python abstract class.


The syntax for Abstract Class


from abc, import ABC, abstractmethod 
class <class name>(ABC):
@abstractmethod 
def <method name>(): 
#abstract class definition

Python Abstract Class Explanation


from abc import ABC, abstractmethod
class AbsBaseClass(ABC):
def __init__(self):
print("Abstract class")
@abstractmethod
def abMeth(self):
pass
def conMeth(self):
print("I'm a concrete method")
class Derived(AbsBaseClass):
def abMeth(self):
print("I'm redefined")
o=Derived()
o.abMeth()
o.conMeth()




References

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