SQL Server Interview Questions and Answers

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SQL Server Interview Questions & Answers :-

• Question 1 :- Explain normalization ?
• Question 2 :- How to implement normalization ?
• Question 3 :- What is denormalization ?
• Question 4 :- Explain OLTP vs OLAP ?
• Question 5 :- Explain 1st,2nd and 3rd Normal form ?
• Question 6 :- Primary Key vs Unique key ?
• Question 7 :- Differentiate between Char vs Varchar ?
• Question 8 :- Differentiate between Char vs NChar ?
• Question 9 :- Whats the size of Char vs NChar ?
• Question 10 :- What is the use of Index ?
• Question 11 :- How does it make search faster?
• Question 12 :- What are the two types of Indexes ?
• Question 13 :- Clustered vs Non-Clustered index?
• Question 14 :- Function vs Stored Procedures?
• Question 15 :- What are triggers and why do you need it ?
• Question 16 :- What are types of triggers ?
• Question 17 :- Differentiate between After trigger vs Instead Of ?
• Question 18 :- What is need of Identity ?
• Question 19 :- Explain transactions and how to implement it ?
• Question 20 :- What are inner joins ?
• Question 21 :- Explain Left join ?
• Question 22 :- Explain Right join ?
• Question 23 :- Explain Full outer joins ?
• Question 24 :- Explain Cross joins ?
• Question 25 :- Why do we need UNION ?
• Question 26 :- Differentiate between Union vs Union All ?
• Question 27 :- Can we have unequal columns in Union?
• Question 28 :- Can column have different data types in Union ?
• Question 29 :- Which Aggregate function have you used ?
• Question 30 :- When to use Group by ?
• Question 31 :- Can we select column which is not part of group by ?
• Question 32 :- What is having clause ?
• Question 33 :- Having clause vs Where clause?
• Question 34 :- How can we sort records ?
• Question 35 :- Whats the default sort ?
• Question 36 :- How can we remove duplicates ?
• Question 37 :- Select the first top X records ?
• Question 38 :- How to handle NULLS ?
• Question 39 :- What is use of wild cards ?
• Question 40 :- What is the use of Alias ?
• Question 41 :- How to write a case statement ?
• Question 42 :- What is self reference tables ?
• Question 43 :- What is self join ?
• Question 44 :- Explain the between clause ?
• Question 45 :- Explain SubQuery ?
• Question 46 :- Can inner Subquery return multiple results ?
• Question 47 :- What is Co-related Query ?
• Question 48 :- Differentiate between Joins and SubQuery ?
• Question 49 :- Performance Joins vs SubQuery?
• Question 50 :- Find NTH Highest Salary in SQL.
• Question 51 :- Select the top nth highest salary using correlated Queries?
• Question 52 :- Select top nth using using TSQL
• Question 53 :- Performance comparison of all the methods.
• Question 54 :- What is CTE ?
• Question 55 :- Can we execute CTE multiple times ?
• Question 56 :- What is use of CTE ?
• Question 57 :- How to write a recursive CTE ?
• Question 58 :- Can we see some real world examples of CTE ?
• Question 59 :- Can we perform insert updates on CTE?
• Question 60 :- Does is update the tables physically ?
• Question 61 :- What are temporary tables?
• Question 62 :- Temp tables vs CTE
• Question 63 :- Performance CTE vs Temp
• SQL Server interview questions with answers PDF.