100 Must-Know T-SQL Interview Questions and Answers 2024

T-SQL Fundamentals

1.
What is T-SQL and how is it different from standard SQL?
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2.
Explain the use of the SELECT statement in T-SQL.
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3.
What are the basic components of a T-SQL query?
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4.
How do you write a T-SQL query to filter data using the WHERE clause?
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5.
Describe how to sort data using the ORDER BY clause in T-SQL.
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6.
What are JOINs in T-SQL and can you explain the different types?
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7.
How do you implement paging in T-SQL queries?
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8.
What is the difference between UNION and UNION ALL?
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9.
How are aliases used in T-SQL queries?
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10.
Can you explain the GROUP BY and HAVING clauses in T-SQL?
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Data Manipulation and Conversion

11.
What are the T-SQL commands for inserting, updating, and deleting data?
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12.
How do you perform a conditional update in T-SQL?
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13.
What is the purpose of the COALESCE function?
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14.
Explain how to convert data types in T-SQL.
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15.
How do you handle NULL values in T-SQL?
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T-SQL Advanced Query Techniques

16.
What is a CTE (Common Table Expression) and how would you use it?
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17.
Explain the purpose and usage of subqueries in T-SQL.
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18.
Describe recursive CTEs and provide an example of when they might be used.
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19.
Can you explain the concept of window functions in T-SQL?
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20.
What is the difference between RANK, DENSE_RANK, and ROW_NUMBER functions?
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21.
Explain how to use the PIVOT and UNPIVOT operators.
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22.
Discuss the use of the OVER clause in T-SQL.
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23.
How can you concatenate rows into a single string in T-SQL?
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T-SQL Functions and Stored Procedures

24.
What are the scalar and table-valued functions in T-SQL?
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25.
How is a stored procedure different from a function in T-SQL?
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26.
Can you write a simple stored procedure with input and output parameters?
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27.
Explain how to handle errors in stored procedures.
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28.
How do you use the EXECUTE statement in T-SQL?
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29.
What is the significance of the RETURN statement in stored procedures?
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30.
Describe the use of table variables and temporary tables in stored procedures.
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T-SQL Programming Constructs

31.
Discuss the use of variables in T-SQL.
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32.
How do you use control-of-flow language (IF…ELSE, WHILE) in T-SQL scripts?
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33.
Can you provide an example of a T-SQL CASE statement?
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34.
Explain the TRY…CATCH construct in T-SQL error handling.
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35.
What are the implications of using CURSORs in T-SQL?
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T-SQL Transaction Management

36.
What is a transaction in the context of T-SQL?
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37.
How do you use the BEGIN TRANSACTION, COMMIT, and ROLLBACK statements?
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38.
What does it mean to set a transaction isolation level in T-SQL?
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39.
Discuss the potential risks of transaction deadlocks.
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T-SQL Indexing and Performance

40.
What is an index in SQL Server and how is it implemented in T-SQL?
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41.
What are clustered and non-clustered indexes?
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42.
How can indexing impact the performance of T-SQL queries?
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43.
Discuss the process and reason for index maintenance.
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44.
What are included columns in an index and when would you use them?
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T-SQL Security

45.
How do you manage permissions using T-SQL?
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46.
What are roles in SQL Server and how are they used in T-SQL?
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47.
Explain the use of T-SQL statements for managing login accounts.
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48.
How can you secure data against SQL injection attacks in T-SQL?
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T-SQL Best Practices

49.
What best practices should be followed when writing T-SQL code?
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50.
How do you write T-SQL code for scalability and maintainability?
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51.
Discuss naming conventions and their importance in T-SQL.
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52.
How do you ensure that your T-SQL code is readable?
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T-SQL Advanced Topics

53.
What are dynamic SQL queries and how do you execute them in T-SQL?
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54.
How is XML data handled in T-SQL?
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55.
What is the difference between SQL Server temporary tables and table variables?
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56.
How do you work with hierarchies and recursive relationships in T-SQL?
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57.
Explain the use of spatial data types in T-SQL.
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Troubleshooting and Optimization

58.
What steps would you take to troubleshoot and optimize a slow-running T-SQL query?
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59.
Explain the use of SQL Server Profiler and Execution Plan for performance tuning.
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60.
How do you identify and handle SQL Server blocking queries?
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T-SQL and Data Warehousing

61.
How does T-SQL support data warehousing operations?
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62.
Describe the use of partitioning in T-SQL and SQL Server.
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63.
Explain the ETL (Extract, Transform, Load) process in relation to T-SQL scripting.
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T-SQL and Business Logic

64.
How do you enforce business logic within T-SQL scripts?
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65.
Describe the use of constraints and triggers in enforcing integrity.
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66.
What are some ways T-SQL can be used for data validation?
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T-SQL Integration with SQL Server Features

67.
How does T-SQL work with SQL Server Reporting Services (SSRS)?
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68.
Discuss the interaction between T-SQL and SQL Server Integration Services (SSIS).
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69.
Explain how T-SQL scripts can be used within SQL Server Agent jobs.
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T-SQL for Data Analysis

70.
How can T-SQL be used for data aggregation and summary?
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71.
Discuss the capabilities of T-SQL for trend analysis.
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72.
How is T-SQL used to prepare data for business intelligence and analytics?
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T-SQL and New Features

73.
What are some of the new T-SQL features in the latest version of SQL Server?
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74.
Discuss how T-SQL has evolved to work with big data and in-memory technologies.
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75.
How does T-SQL support cloud scenarios with Azure SQL Database?
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Advanced Data Manipulation

76.
Explain strategies for handling large-volume data updates and deletes in T-SQL.
Answer:
77.
How do you use T-SQL to handle duplicate record scenarios?
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78.
What is a T-SQL Merge statement and how is it used?
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T-SQL Testing and Debugging

79.
What tools and techniques are available for testing T-SQL code?
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80.
How can you debug a stored procedure in SQL Server Management Studio (SSMS)?
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81.
Discuss how assertions and checkpoints can be used in T-SQL scripts.
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Handling Date and Time in T-SQL

82.
Discuss how to work with different date and time data types in T-SQL.
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83.
How do you handle time zones in T-SQL?
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84.
Provide examples of common date and time-related functions in T-SQL.
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T-SQL and Advanced Data Types

85.
How does T-SQL accommodate working with JSON data?
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86.
What support does T-SQL offer for working with binary and large objects (BLOBs)?
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87.
Discuss the use of UDT (User-Defined Types) in T-SQL.
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T-SQL Deployment Practices

88.
How do you manage T-SQL script deployments across different environments?
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89.
Discuss version control practices for T-SQL scripts.
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T-SQL for Database Administration

90.
How do you automate common database administration tasks with T-SQL?
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91.
Discuss the T-SQL scripts for backing up and restoring SQL Server databases.
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92.
Explain how to monitor SQL Server health with T-SQL scripts.
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Advanced Stored Procedure Techniques

93.
Discuss the use of output parameters in stored procedures.
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94.
How do dynamic stored procedures work?
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95.
How can you manage transaction scope within a stored procedure?
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T-SQL and Collaboration

96.
How do you document your T-SQL code for team collaboration?
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97.
Discuss the role of code reviews in the T-SQL development process.
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Real-world Scenario-based T-SQL Questions

98.
How would you design a T-SQL solution for a banking transaction system?
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99.
Provide a T-SQL solution for reporting top N customers by sales.
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100.
Discuss how you would use T-SQL to identify and resolve data integrity issues.
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100 T-SQL interview questions

What is T-SQL and how is it different from standard SQL?

Explain the use of the SELECT statement in T-SQL.

What are the basic components of a T-SQL query?

How do you write a T-SQL query to filter data using the WHERE clause?

Describe how to sort data using the ORDER BY clause in T-SQL.

What are JOINs in T-SQL and can you explain the different types?

How do you implement paging in T-SQL queries?

What is the difference between UNION and UNION ALL?

How are aliases used in T-SQL queries?

Can you explain the GROUP BY and HAVING clauses in T-SQL?

What are the T-SQL commands for inserting, updating, and deleting data?

How do you perform a conditional update in T-SQL?

What is the purpose of the COALESCE function?

Explain how to convert data types in T-SQL.

How do you handle NULL values in T-SQL?

What is a CTE (Common Table Expression) and how would you use it?

Explain the purpose and usage of subqueries in T-SQL.

Describe recursive CTEs and provide an example of when they might be used.

Can you explain the concept of window functions in T-SQL?

What is the difference between RANK, DENSE_RANK, and ROW_NUMBER functions?

Explain how to use the PIVOT and UNPIVOT operators.

Discuss the use of the OVER clause in T-SQL.

How can you concatenate rows into a single string in T-SQL?

What are the scalar and table-valued functions in T-SQL?

How is a stored procedure different from a function in T-SQL?

Can you write a simple stored procedure with input and output parameters?

Explain how to handle errors in stored procedures.

How do you use the EXECUTE statement in T-SQL?

What is the significance of the RETURN statement in stored procedures?

Describe the use of table variables and temporary tables in stored procedures.

Discuss the use of variables in T-SQL.

How do you use control-of-flow language (IF…ELSE, WHILE) in T-SQL scripts?

Can you provide an example of a T-SQL CASE statement?

Explain the TRY…CATCH construct in T-SQL error handling.

What are the implications of using CURSORs in T-SQL?

What is a transaction in the context of T-SQL?

How do you use the BEGIN TRANSACTION, COMMIT, and ROLLBACK statements?

What does it mean to set a transaction isolation level in T-SQL?

Discuss the potential risks of transaction deadlocks.

What is an index in SQL Server and how is it implemented in T-SQL?

What are clustered and non-clustered indexes?

How can indexing impact the performance of T-SQL queries?

Discuss the process and reason for index maintenance.

What are included columns in an index and when would you use them?

How do you manage permissions using T-SQL?

What are roles in SQL Server and how are they used in T-SQL?

Explain the use of T-SQL statements for managing login accounts.

How can you secure data against SQL injection attacks in T-SQL?

What best practices should be followed when writing T-SQL code?

How do you write T-SQL code for scalability and maintainability?

Discuss naming conventions and their importance in T-SQL.

How do you ensure that your T-SQL code is readable?

What are dynamic SQL queries and how do you execute them in T-SQL?

How is XML data handled in T-SQL?

What is the difference between SQL Server temporary tables and table variables?

How do you work with hierarchies and recursive relationships in T-SQL?

Explain the use of spatial data types in T-SQL.

What steps would you take to troubleshoot and optimize a slow-running T-SQL query?

Explain the use of SQL Server Profiler and Execution Plan for performance tuning.

How do you identify and handle SQL Server blocking queries?

How does T-SQL support data warehousing operations?

Describe the use of partitioning in T-SQL and SQL Server.

Explain the ETL (Extract, Transform, Load) process in relation to T-SQL scripting.

How do you enforce business logic within T-SQL scripts?

Describe the use of constraints and triggers in enforcing integrity.

What are some ways T-SQL can be used for data validation?

How does T-SQL work with SQL Server Reporting Services (SSRS)?

Discuss the interaction between T-SQL and SQL Server Integration Services (SSIS).

Explain how T-SQL scripts can be used within SQL Server Agent jobs.

How can T-SQL be used for data aggregation and summary?

Discuss the capabilities of T-SQL for trend analysis.

How is T-SQL used to prepare data for business intelligence and analytics?

What are some of the new T-SQL features in the latest version of SQL Server?

Discuss how T-SQL has evolved to work with big data and in-memory technologies.

How does T-SQL support cloud scenarios with Azure SQL Database?

Explain strategies for handling large-volume data updates and deletes in T-SQL.

How do you use T-SQL to handle duplicate record scenarios?