Sql Interview Questions

August 2, 2016 by Giryavva Ghodake

Filed under SQL

Last modified August 2, 2016

Sql Interview Questions

  1. What is DBMS ?
  2. What is RDBMS ?
  3. What is SQL ?
  4. What are the different type of SQL’s statements ?
  5. What are the Advantages of SQL ?
  6. what is a field in a database ?
  7. What is a Record in a database ?
  8. What is a Table in a database ?
  9. What is a database transaction?
  10. What are properties of a transaction?
  11. What is a Database Lock ?What are the type of locks ?
  12. What are the different type of normalization?
  13. What is a primary key?
  14. What is the difference between SQL and MySQL or SQL Server?
  15. What is the difference between SQL and PL/SQL?
  16. What are various DDL commands in SQL?
  17. Give brief description of their purposes.
  18. What are various DML commands in SQL?
  19. Give brief description of their purposes.
  20. What are various DCL commands in SQL? Give brief description of their purposes.
  21. Can you sort a column using a column alias?
  22. Is a NULL value same as zero or a blank space? If not then what is the difference?
  23. If a column value taking part in an arithmetic expression is NULL, then the result obtained would be NULLM.
  24. If a table contains duplicate rows, does a query result display the duplicate values by default? How can you eliminate duplicate rows from a query result?
  25. What is the purpose of the condition operators BETWEEN and IN?
  26. How do you search for a value in a database table when you don’t have the exact value to search for?
  27. What is the default ordering of data using the ORDER BY clause? How could it be changed?
  28. What are the specific uses of SQL functions?
  29. What are the case manipulation functions of SQL?
  30. Which function returns the remainder in a division operation?
  31. What is the purpose of the NVL function?
  32. What is the difference between the NVL and the NVL2 functions?
  33. What is the use of the NULL IF function?
  34. Discuss the syntax and use of the COALESCE function?
  35. Which expressions or functions allow you to implement conditional processing in a SQL statement?
  36. You want to display a result query from joining two tables with 20 and 10 rows respectively. Erroneously you forget to write the WHERE clause. What would be the result?
  37.  What is the difference between cross joins and natural joins?
  38. What is the purpose of the group functions in SQL?
  39. Give some examples of group functions.
  40. What do you understand by a subquery? When is it used?
  41. What’s wrong in the following query?
  42.    SELECT student_code, name
  43.    FROM students
  44.    WHERE marks =
  45.                (SELECT MAX(marks)
  46.                   FROM students
  47.                   GROUP BY subject_code);
  48. What are the various multiple row comparison operators in SQL?
  49.  What is the pupose of DML statements in SQL?
  50. Which statement is used to add a new row in a database table?
  51. How do you insert null values in a column while inserting data?
  52. How do you copy rows from one table to another?
  53. What happens if you omit the WHERE clause in the UPDATE statement?
  54. Can you modify the rows in a table based on values from another table?
  55. What happens if you omit the WHERE clause in a delete statement? Can you remove rows from a table based on values from another table?
  56. What is the purpose of the MERGE statement in SQL?
  57. What is the difference between VARCHAR2 AND CHAR datatypes?
  58. Which SQL statement is used to add, modify or drop columns in a database table?
  59. What is a view? Why should you use a view?

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