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NTT DATA Corp (NTT Data), a subsidiary of Nippon Telegraph and Telephone Corp, is a provider of IT services and solutions. The company develops, maintains, sells and rents data communication systems. It offers IT services including consulting services, enterprise application services, application development and management, sap solutions, cloud solutions, cyber security services, infrastructure services, Oracle solutions, consulting services, data and intelligence services and architecture services. NTT Data offers services to public administration, healthcare, financial institutions, education, the automotive industry, manufacturing, retail, logistics, energy and utilities, and telecommunications. The company has sales offices in the Americas, Europe, the Middle East and Asia Pacific. NTT Data is headquartered in Koto-Ku, Tokyo, Japan.
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Why Join in NTT DATA
1. Professional Tone
It is a leading global IT services company that offers a wide range of technology services, including cloud computing, data centers, networking, software development and enterprise applications. Working at nttdata.com would allow me to gain valuable IT experience and knowledge and expand my skills.
2. Funny Tone
This is a great company with lots of opportunities for growth and development. Plus, the people who work there really seem to love their jobs and are always willing to help and answer any questions you might have.
3. Informal Tone
This is a great company with lots of opportunities for growth and development.
NTT DATA SQL Interview Preparation Tips
Coming to an interview with a defined plan of action is often the best method of keeping pre-interview jitters at bay. Even if you are worried, the following tips and approach can organize your ideas and lead you to a solution, no matter what question you should ask.
- To understand and understand what you have been told to achieve, repeat the question in your mind.
- You can learn more about the information by asking about it. What kind of data is reserved for each column? Is there any data in other columns that is different (eg login number)?
- Determine which columns you will need to solve the query. This allows you to focus on the data that counts and not be distracted by data that is not relevant to the question at hand.
- Consider what you want your answer to look like. Do you want a single item or a collection of values? Will the equation be the solution? Will it be a float or a number? Is this something you need to account for in your code?
- Build your code step by step without rushing. It’s a good idea to plan your strategy in advance. Once you start writing your query, you will have a clear framework if you write the stages you want to go through.
- Then code in short iterations, taking one piece at a time as you plan. Once you are happy with the code for the first step, continue with the following.
- Overall, describe your approach. Show if there is a better method for writing the code, such as using subqueries. Also, don’t forget to answer the question lightly.
- Say your steps out loud as you go through them. You should make it clear to your HR person, who may not be very familiar with SQL, what, why and how to perform each action.
- Include a textual description of what each stage of your questioning is intended to accomplish. This can help you track your progress in the query and also increase code clarity. You can also enter side comments if you are programming in a live environment.
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Top NTT DATA SQL Interview Question and Answers
1. What is SQL?
SQL stands for Structured Query Language. It is a language used to interact with the database, i.e to create a database, to create a table in the database, to retrieve data or update a table in the database, etc. SQL is an ANSI(American National Standards Institute) standard. Using SQL, we can do many things. For example – we can execute queries, we can insert records into a table, can update records, can create a database, can create a table, can delete a table, etc.
2. What is a database?
A Database is defined as a structured form of data storage in a computer or a collection of data in an organized manner and can be accessed in various ways. It is also the collection of schemas, tables, queries, views, etc. Databases help us with easily storing, accessing, and manipulating data held on a computer. The Database Management System allows a user to interact with the database.
3. Does SQL support programming language features?
It is true that SQL is a language, but it does not support programming as it is not a programming language, it is a command language. We do not have conditional statements in SQL like for loops or if..else, we only have commands which we can use to query, update, delete, etc. data in the database. SQL allows us to manipulate data in a database.
4. What is the difference between CHAR and VARCHAR2 datatype in SQL?
Both of these data types are used for characters, but varchar2 is used for character strings of variable length, whereas char is used for character strings of fixed length. For example, if we specify the type as char(5) then we will not be allowed to store a string of any other length in this variable, but if we specify the type of this variable as varchar2(5) then we will be allowed to store strings of variable length. We can store a string of length 3 or 4 or 2 in this variable.
5. What do you mean by data definition language?
Data definition language or DDL allows to execution of queries like CREATE, DROP, and ALTER. That is those queries that define the data.
6. What do you mean by data manipulation language?
Data manipulation Language or DML is used to access or manipulate data in the database. It allows us to perform the below-listed functions:
- Insert data or rows in a database
- Delete data from the database
- Retrieve or fetch data
- Update data in a database.
7. What are table and Field?
Table: A table has a combination of rows and columns. Rows are called records and columns are called fields. In MS SQL Server, the tables are being designated within the database and schema names.
Field: In DBMS, a database field can be defined as – a single piece of information from a record.
8. What is the primary key?
A Primary Key is one of the candidate keys. One of the candidate keys is selected as the most important and becomes the primary key. There cannot be more than one primary key in a table.
9. What is a Default constraint?
The DEFAULT constraint is used to fill a column with default and fixed values. The value will be added to all new records when no other value is provided.
10. What is normalization?
It is a process of analyzing the given relation schemas based on their functional dependencies and primary keys to achieve the following desirable properties:
- Minimizing Redundancy
- Minimizing the Insertion, Deletion, And Update Anomalies
Relation schemas that do not meet the properties are decomposed into smaller relation schemas that could meet desirable properties.
11. What is Denormalization?
Denormalization is a database optimization technique in which we add redundant data to one or more tables. This can help us avoid costly joins in a relational database. Note that denormalization does not mean not doing normalization. It is an optimization technique that is applied after normalization.
In a traditional normalized database, we store data in separate logical tables and attempt to minimize redundant data. We may strive to have only one copy of each piece of data in the database.
12. What is a query?
An SQL query is used to retrieve the required data from the database. However, there may be multiple SQL queries that yield the same results but with different levels of efficiency. An inefficient query can drain the database resources, reduce the database speed or result in a loss of service for other users. So it is very important to optimize the query to obtain the best database performance.
13. What is a subquery?
In SQL, a Subquery can be simply defined as a query within another query. In other words, we can say that a Subquery is a query that is embedded in the WHERE clause of another SQL query.
14. What are the different operators available in SQL?
There are three operators available in SQL namely:
- Arithmetic Operators
- Logical Operators
- Comparison Operators
15. What is a Constraint?
Constraints are the rules that we can apply to the type of data in a table. That is, we can specify the limit on the type of data that can be stored in a particular column in a table using constraints.
16. What is Data Integrity?
Data integrity is defined as the data contained in the database being both correct and consistent. For this purpose, the data stored in the database must satisfy certain types of procedures (rules). The data in a database must be correct and consistent. So, data stored in the database must satisfy certain types of procedures (rules). DBMS provides different ways to implement such types of constraints (rules). This improves data integrity in a database.
17. What is Auto Increment?
Sometimes, while creating a table, we do not have a unique identifier within the table, hence we face difficulty in choosing Primary Key. So as to resolve such an issue, we’ve to manually provide unique keys to every record, but this is often also a tedious task. So we can use the Auto-Increment feature that automatically generates a numerical Primary key value for every new record inserted. The Auto Increment feature is supported by all the Databases.
18. What is MySQL collation?
A MySQL collation is a well-defined set of rules which are used to compare characters of a particular character set by using their corresponding encoding. Each character set in MySQL might have more than one collation, and has, at least, one default collation. Two character sets cannot have the same collation.
19. What are user-defined functions?
We can use User-defined functions in PL/SQL or Java to provide functionality that is not available in SQL or SQL built-in functions. SQL functions and User-defined functions can appear anywhere, that is, wherever an expression occurs.
For example, it can be used in:
- Select a list of SELECT statements.
- Condition of the WHERE clause.
- CONNECT BY, ORDER BY, START WITH, and GROUP BY
- The VALUES clause of the INSERT statement.
- The SET clause of the UPDATE statement.
20. What are all types of user-defined functions?
User-Defined Functions allow people to define their own T-SQL functions that can accept 0 or more parameters and return a single scalar data value or a table data type.
Different Kinds of User-Defined Functions created are:
1. Scalar User-Defined Function A Scalar user-defined function returns one of the scalar data types. Text, image, and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. You pass in 0 to many parameters and you get a return value.
2. Inline Table-Value User-Defined Function An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and, in essence, provide us with a parameterized, non-updateable view of the underlying tables.
3. Multi-statement Table-Value User-Defined Function A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view, as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a TSQL select command or a group of them gives us the capability to, in essence, create a parameterized, non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function, it can be used in the FROM clause of a T-SQL command, unlike the behavior found when using a stored procedure which can also return record sets.
21. What is a stored procedure?
Stored Procedures are created to perform one or more DML operations on databases. It is nothing but a group of SQL statements that accepts some input in the form of parameters and performs some task and may or may not return a value.
22. What are aggregate and scalar functions?
For doing operations on data SQL has many built-in functions, they are categorized into two categories and further sub-categorized into seven different functions under each category. The categories are:
- Aggregate functions: These functions are used to do operations from the values of the column and a single value is returned.
- Scalar functions: These functions are based on user input, these too return a single value.
23. What is an ALIAS command?
Aliases are the temporary names given to a table or column for the purpose of a particular SQL query. It is used when the name of a column or table is used other than its original name, but the modified name is only temporary.
- Aliases are created to make table or column names more readable.
- The renaming is just a temporary change and the table name does not change in the original database.
- Aliases are useful when table or column names are big or not very readable.
- These are preferred when there is more than one table involved in a query.
24. What is a T-SQL?
T-SQL is an abbreviation for Transact Structure Query Language. It is a product by Microsoft and is an extension of SQL Language which is used to interact with relational databases. It is considered to perform best with Microsoft SQL servers. T-SQL statements are used to perform the transactions to the databases. T-SQL has huge importance since all the communications with an instance of an SQL server are done by sending Transact-SQL statements to the server. Users can also define functions using T-SQL.
Types of T-SQL functions are :
- Aggregate functions.
- Ranking functions. There are different types of ranking functions.
- Rowset function.
- Scalar functions.
25. What is ETL in SQL?
ETL is a process in Data Warehousing and it stands for Extract, Transform, and Load. It is a process in which an ETL tool extracts the data from various data source systems, transforms it in the staging area, and then finally, loads it into the Data Warehouse system. These are three database functions that are incorporated into one tool to pull data out from one database and put data into another database.
26. What is the difference between primary key and unique constraints?
The primary key cannot have NULL values, the unique constraints can have NULL values. There is only one primary key in a table, but there can be multiple unique constraints. The primary key creates the clustered index automatically but the unique key does not.
27. What is a join in SQL? What are the types of joins?
An SQL Join statement is used to combine data or rows from two or more tables based on a common field between them. Different types of Joins are:
- INNER JOIN: The INNER JOIN keyword selects all rows from both tables as long as the condition is satisfied. This keyword will create the result set by combining all rows from both the tables where the condition satisfies i.e. the value of the common field will be the same.
- LEFT JOIN: This join returns all the rows of the table on the left side of the join and matching rows for the table on the right side of the join. For the rows for which there is no matching row on the right side, the result set will be null. LEFT JOIN is also known as LEFT OUTER JOIN
- RIGHT JOIN: RIGHT JOIN is similar to LEFT JOIN. This join returns all the rows of the table on the right side of the join and matching rows for the table on the left side of the join. For the rows for which there is no matching row on the left side, the result set will contain null. RIGHT JOIN is also known as RIGHT OUTER JOIN.
- FULL JOIN: FULL JOIN creates the result set by combining the results of both LEFT JOIN and RIGHT JOIN. The result set will contain all the rows from both tables. For the rows for which there is no matching, the result set will contain NULL values.
28. What is an index?
A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes and the use of more storage space to maintain the extra copy of data. Data can be stored only in one order on a disk. To support faster access according to different values, a faster search like a binary search for different values is desired. For this purpose, indexes are created on tables. These indexes need extra space on the disk, but they allow faster search according to different frequently searched values.
29. What is the On Delete cascade constraint?
An ‘ON DELETE CASCADE’ constraint is used in MySQL to delete the rows from the child table automatically when the rows from the parent table are deleted.
30. Explain WITH clause in SQL?
The WITH clause provides a way relationship of defining a temporary relationship whose definition is available only to the query in which the with clause occurs. SQL applies predicates in the WITH clause after groups have been formed, so aggregate functions may be used.
31. What are all the different attributes of indexes?
The indexing has various attributes:
- Access Types: This refers to the type of access such as value-based search, range access, etc.
- Access Time: It refers to the time needed to find a particular data element or set of elements.
- Insertion Time: It refers to the time taken to find the appropriate space and insert new data.
- Deletion Time: Time is taken to find an item and delete it as well as update the index structure.
- Space Overhead: It refers to the additional space required by the index.
32. What is a Cursor?
The cursor is a Temporary Memory or Temporary Work Station. It is Allocated by Database Server at the Time of Performing DML operations on the Table by the User. Cursors are used to store Database Tables. 8. Write down various types of relationships in SQL?
There are various relationships, namely:
- One-to-One Relationship.
- One to Many Relationships.
- Many to One Relationship.
- Self-Referencing Relationship.
33. What is a trigger?
The trigger is a statement that a system executes automatically when there is any modification to the database. In a trigger, we first specify when the trigger is to be executed and then the action to be performed when the trigger executes. Triggers are used to specify certain integrity constraints and referential constraints that cannot be specified using the constraint mechanism of SQL.
34. What are local and global variables and their differences?
Global Variable: In contrast, global variables are variables that are defined outside of functions. These variables have global scope, so they can be used by any function without passing them to the function as parameters.
Local Variable: Local variables are variables that are defined within functions. They have local scope, which means that they can only be used within the functions that define them.
35. Define SQL Order by the statement?
The ORDER BY statement in SQL is used to sort the fetched data in either ascending or descending according to one or more columns.
- By default ORDER BY sorts the data in ascending order.
- We can use the keyword DESC to sort the data in descending order and the keyword ASC to sort in ascending order.
36.Explain SQL Having statement?
HAVING is used to specify a condition for a group or an aggregate function used in the select statement. The WHERE clause selects before grouping. The HAVING clause selects rows after grouping. Unlike the HAVING clause, the WHERE clause cannot contain aggregate functions.
37. Explain SQL AND OR statement with an example?
In SQL, the AND & OR operators are used for filtering the data and getting precise results based on conditions. The AND and OR operators are used with the WHERE clause.
These two operators are called conjunctive operators.
- AND Operator: This operator displays only those records where both conditions condition 1 and condition 2 evaluate to True.
- OR Operator: This operator displays the records where either one of the conditions condition 1 and condition 2 evaluates to True. That is, either condition1 is True or condition2 is True.
38. Define BETWEEN statements in SQL?
The SQL BETWEEN condition allows you to easily test if an expression is within a range of values (inclusive). The values can be text, date, or numbers. It can be used in a SELECT, INSERT, UPDATE, or DELETE statement. The SQL BETWEEN Condition will return the records where the expression is within the range of value1 and value2.
39. What are ACID properties?
A transaction is a single logical unit of work that accesses and possibly modifies the contents of a database. Transactions access data using read-and-write operations. In order to maintain consistency in a database, before and after the transaction, certain properties are followed. These are called ACID properties. ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably.
40. Are NULL values the same as zero or a blank space?
In SQL, zero or blank space can be compared with another zero or blank space. whereas one null may not be equal to another null. null means data might not be provided or there is no data.
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Conclusion
In conclusion, mastering SQL interview questions is crucial. This article provides a comprehensive set of NTT DATA SQL Interview Questions and Answers designed to prepare you thoroughly.
By understanding and practicing these questions, you will improve your ability to effectively solve SQL interview challenges, ultimately paving the way for a successful career in data processing and analytics. Remember that every question is an opportunity to demonstrate your analytical prowess and technical expertise, essential qualities for any aspiring professional in these critical roles.
