Mostly Asked Interview Questions For Data Engineer, Data Analyst, BI Engineer and Data Science

 Most Asked Interview Questions For Data Engineer, Data Analyst, BI Engineer, and Data Science

In this post, I am sharing a list of the most asked questions in the interview for Data Engineer, Data Analyst, BI Engineer, and Data Science.

Must Read: SQL-server-day-today-mostly-used functions

- Data Types:

    Small Int

    Int

    Big Int

    Float

    Decimal

    Money

    Char

    Varchar

    Nvarchar

    Text

    Binary

    Image

    Date

    DateTime

    Timestamp

    Bit

-  Functions:

    Scalar Functions: Operate on a single value and then return a single value. Scalar functions can be used wherever an expression is valid.

        UCASE()

        LCASE()

        MID()

        LEN()

        ROUND()

        NOW()

        FORMAT()

    Aggregate Functions: Aggregate functions perform a calculation on a set of values and return a single value.

        Min

        Max

        Avg

        Count

        Sum

        Mod

        First

        Last

    Analytical Functions: Analytic functions compute an aggregate value based on a group of rows.

        First_Value

        Last_Value

        LAG

        Lead

        Percentile_Cont

        Percentile_Disc

        Percentile_Rank

    Ranking Function: Ranking functions return a ranking value for each row in a partition.

        Rank    

        Row_Number

        Dense_Rank

        NILE

    String Function: The string function return a value to perform some operations on the string value.

        Substr

        CharIndex

        PatIndex

        Replace

        Left

        Right

        LTrim

        RTrim

        Len

Date Functions: Date functions are used to perform some operations on the date value.

    DateAdd

    DateDiff

    DatePart

    DateName

    Year

    Month

    Getdate()

- What is @@Error?

- Difference between DDL, DML, and DCL.

- What type of clause in SQL?

    Ans: Where, Group BY, Order By

- What is Constraint in SQL?

- Difference between  Temp variable, Temp Table?

- Difference between Local Temporary Tables and Global Temporary Tables?

- How we can schedule a job in SQL Server?

    Ans: SQL Server Agent

- What is NOLock?

- What type of joins do we have in SQL?

- What are Logical Joins and Physical Joins?

- Difference between Inner Join and Left Join?

- What is Cross Join?

- What are Cross Apply and Outer Apply?

- Difference between Functions and Stored Procedure?

- Difference between the Delete table and the Truncate table?

- Difference between Varchar() and Nvarchar()?

- Difference between Cast and Convert?

- Difference between View and CTE?

- What is Indexed View?

- Can we Insert or update in views?

- What is Index in SQL and type of Indexes in SQL?

- Difference between Primary Key, Foreign Key, and Unique Key?

- What is Database Partitioning?

- What are Triggers in Database?

- What is Window Functions?

- Difference between Having and Group By?

- What is an Execution Plan?

- what are IN-memory Tables?

- What is Always on?

- What Is Data Encryption?

- What is the difference between ISNULL, NVL, and Coalesce?

Scenarios based Questions:

- How to improve the performance of slow-running queries?

OR

- Define approaches to tune the queries and improve the performance?

- How to calculate the running total?

- Find 3rd highest salary from the employee table?

- From the employee table, show the manager of each employee?

- Implementation of Joins for a given data

- How to remove duplicates from the table?

- How do get the latest order for each customer?

- Show highest-paid and Lowest paid employee from each Department

- Top five highest selling products from each product category in past one quarter?

Stay tuned for more details.

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