Navaratan Technologies Senior SQL Developer Interview Questions and Answers

Q1. What are Types of joins
Ans. 
Types of joins in SQL are Inner Join, Left Join, Right Join, and Full Join.
• Inner Join: Returns rows when there is a match in both tables.

• Left Join: Returns all rows from the left table and the matched rows from the right table.

• Right Join: Returns all rows from the right table and the matched rows from the left table.

• Full Join: Returns rows when there is a match in one of the tables.
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Q2. Difference between groupby and having clause
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GROUP BY is used to group rows that have the same values into summary rows, while HAVING is used to filter groups based on a specified condition.
• GROUP BY is used with aggregate functions to group the result set by one or more columns.

• HAVING is used to filter groups based on a specified condition after the GROUP BY clause.

• GROUP BY is used before the HAVING clause in a query.

• Example: SELECT department, COUNT(*) FROM empl
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Q3. What are DML commands
Ans. 
DML commands are Data Manipulation Language commands used to manage data in a database.
• DML commands include INSERT, UPDATE, DELETE, and SELECT.

• INSERT is used to add new rows of data into a table.

• UPDATE is used to modify existing data in a table.

• DELETE is used to remove rows of data from a table.

• SELECT is used to retrieve data from a database.
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Q4. Difference between Primary key and Unique key
Ans. 
Primary key uniquely identifies each record in a table, while Unique key allows only one instance of a value in a column.
• Primary key does not allow NULL values, while Unique key allows one NULL value.

• Primary key automatically creates a clustered index, while Unique key creates a non-clustered index by default.

• Primary key can be referenced by foreign keys, while Unique key cannot be referenced by foreign keys.
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Q5. What are Index and types of index
Ans. 
Indexes are data structures that improve the speed of data retrieval operations in a database.
• Indexes are used to quickly locate data without having to search every row in a database table.

• Types of indexes include clustered, non-clustered, unique, and composite indexes.

• Clustered indexes determine the physical order of data in a table, while non-clustered indexes store a separate copy of the indexed columns.

• Unique index...read more
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Q6. What is execution plan
Ans. 
Execution plan is a roadmap that SQL Server uses to execute a query, showing the steps taken to retrieve data.
• Execution plan is generated by the query optimizer to determine the most efficient way to execute a query.

• It shows the order in which tables are accessed, joins are performed, and filters are applied.

• Execution plan can be viewed using tools like SQL Server Management Studio or by using the EXPLAIN statement in
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Q7. Explain about your Project ? challenges faced
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Q8. Write a sql query depart wise max salary
Ans. 
SQL query to retrieve the maximum salary for each department
• Use the MAX() function to find the maximum salary

• Group the results by department using the GROUP BY clause

• Join the employee table with the department table to get the department information
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Q9. Given a table TEAM with only one column teamname, write a sql query where each team play with each other , no duplicate match
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Q10. Provide o/p for innerjoin, left join, right join, cross join on a(1,1,1,2,2,3) b(1,1,2,4)
Ans. 
Different types of SQL joins with given data sets a and b.
• Inner join: Returns rows where there is a match in both tables (1,1)

• Left join: Returns all rows from the left table and the matched rows from the right table (1,1,1,2,2)

• Right join: Returns all rows from the right table and the matched rows from the left table (1,1,2,4)

• Cross join: Returns the Cartesian product of the two tables (1,1,1,1,1,2,1,4,1,1,2,1,2,2,1,4,2,...read more
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Q11. Row_number, rank, dense_rank with example
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row_number, rank, dense_rank are window functions in SQL used to assign a unique number to each row based on specified criteria.
• row_number() assigns a unique sequential integer starting from 1 to each row in the result set

• rank() assigns a unique rank to each row based on the specified ordering criteria, with gaps in ranking for ties

• dense_rank() assigns a unique rank to each row based on the specified ordering criteria,
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Q12. What is trigger
Ans. 
A trigger is a special type of stored procedure that automatically executes when certain events occur in a database.
• Triggers can be used to enforce business rules, maintain referential integrity, and automate repetitive tasks.

• Examples of trigger events include INSERT, UPDATE, and DELETE operations on a table.

• Triggers can be defined to execute before or after the triggering event.
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Q13. Diffrenc between function and store procedure
Ans. 
Functions return a value, while stored procedures do not. Functions can be used in SELECT statements, stored procedures cannot.
• Functions return a single value, while stored procedures can return multiple values or none at all.

• Functions can be used in SELECT statements to return a value, while stored procedures cannot be used in this way.

• Functions can be called from within stored procedures, but stored procedures cannot
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Q1. Explainyour job role
Ans. 
ETL Developers are responsible for designing, developing, and maintaining ETL processes to extract, transform, and load data from various sources into a data warehouse.
• Designing ETL processes to extract data from multiple sources

• Transforming data to meet business requirements

• Loading data into a data warehouse or other target systems

• Developing and maintaining ETL jobs using tools like Informatica, Talend, or SSIS
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Q2. Explain implementation of SCD 1 in IICS
Ans. 
SCD Type 1 in IICS involves overwriting existing data with new data without maintaining historical changes.
• In IICS, use the Mapping Designer to create a mapping that loads data from source to target.

• Use a Lookup transformation to check if the record already exists in the target table.

• If the record exists, update the existing record with new data using an Update Strategy transformation.

• If the record does not exist, inse...read more
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Q1. Basic ios development questions
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Q2. Core data or any other data base
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Normal MCQ questions reasoning, java related and programs outputs

Difference between abstract classes and interfaces, Array sort time complexity

Q1. Questions related to koltin
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Q2. Jetpack compose uses
Ans. 
Jetpack Compose is a modern Android UI toolkit that simplifies and accelerates UI development.
• Declarative UI: Jetpack Compose allows developers to build UI using a declarative programming model.

• State management: Jetpack Compose handles state management efficiently, making it easier to update UI based on data changes.

• Compose functions: Developers can create reusable UI components using Compose functions.

• Interoperability...read more
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Q3. Difference between remember and rememberSaveable
Ans. 
remember is used to store a value in a composable function, while rememberSaveable is used to store a value that survives configuration changes.
• remember is used to store a value that does not survive configuration changes

• rememberSaveable is used to store a value that survives configuration changes, such as rotation of the device

• rememberSaveable is typically used for storing view model data in Jetpack Compose
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Q4. Coroutines parallel and sequential processing
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Q1. Basics of Android
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Q1. Technical implementation
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Q1. Company fit culture test
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Q1. Informtica with date functions
Ans. 
Informatica is a popular ETL tool used for data integration and transformation. It has built-in functions to handle date operations.
• Informatica is a powerful ETL tool used for extracting, transforming, and loading data.

• It provides a variety of built-in functions for handling date operations such as date calculations, formatting, and conversions.

• Examples of date functions in Informatica include TO_DATE, TO_CHAR, ADD_TO_
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Q1. Tell me about ur self
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Q2. And some sql queries and questions
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