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HSBC (The Hongkong and Shanghai Banking Corporation) is one of the world’s largest banking and financial services organisations. Founded in 1865 in Hong Kong and Shanghai, the company was originally established to facilitate trade between China and Europe. Over time, HSBC has expanded its operations globally, becoming a major player in retail banking, commercial banking, investment banking and asset management.
Key HSBC facts:
- Global presence:
HSBC operates in more than 60 countries and territories worldwide, with a strong presence in Asia, Europe, the Americas, the Middle East and Africa. Its headquarters are in London, United Kingdom.
- Business Units:
- Retail Banking and Wealth Management: Provides services such as savings accounts, mortgages, credit cards and investment advice.
- Commercial Banking: Provides services to small and medium-sized businesses, including lending, payments and cash management.
- Markets and World Banking: Provides investment banking services, including corporate finance, trading and securities services.
- Global Private Banking: Provides wealth management services to high-net-worth individuals and families.
- Sustainability Commitments: HSBC has made significant efforts in sustainability, committing to become a net-zero emissions bank by 2050. The bank has set ambitious targets to support the transition to a low-carbon economy by funding clean energy projects and reducing its own carbon emissions.
- Financial strength: HSBC is known for its strong financial position, consistently ranking among the world’s top banks in terms of assets and market capitalisation.
With a long history in banking and a focus on global trade and financial services, HSBC remains a major financial institution that influences economies and industries around the world.
HSBC SQL Interview Questions
Here are some common SQL interview questions that may be asked when interviewing for a position at HSBC or similar financial institutions. These questions cover a wide range of topics, from basic SQL syntax to more complex queries involving data manipulation, joins, subqueries, and performance optimization.
Here are some sample SQL interview questions that may be asked during an interview for a position at HSBC or any similar organization, along with their answers:
1. What is SQL?
Answer: SQL (Structured Query Language) is a standard programming language used to manage and manipulate relational databases. It is used for tasks such as querying data, updating records, and creating and managing database structures.
2. What are the different types of SQL commands?
Answer:
- DDL (Data Definition Language): Used to define and manage database structure. Includes commands such as CREATE, ALTER, DROP, and TRUNCATE.
- DML (Data Manipulation Language): Used to manage data in tables. Includes SELECT, INSERT, UPDATE, and DELETE.
- DCL (Data Control Language): Used to control access to data. Includes GRANT and REVOKE.
- TCL (Transaction Control Language): Used to manage transactions. Includes COMMIT, ROLLBACK, and SAVEPOINT.
3. What is the difference between INNER JOIN and LEFT JOIN?
Answer:
- INNER JOIN: Returns only rows that have a match in both tables. If there is no match, the row is not included.
- LEFT JOIN (or LEFT OUTER JOIN): Returns all rows from the left table and matching rows from the right table. If there is no match, the result will contain NULLs for the columns in the right table.
Example:
SELECT A.name, B.salary
FROM employees A
INNER JOIN salaries B ON A.emp_id = B.emp_id;
SELECT A.name, B.salary
FROM employees A
LEFT JOIN salaries B ON A.emp_id = B.emp_id;
4. What is a primary key and a foreign key?
Answer:
- Primary key: A column or set of columns that uniquely identifies each row in a table. It cannot contain NULL values and must contain unique values.
- Foreign key: A column or set of columns in a table that is used to link data from two tables.
It references the primary key of another table and helps maintain referential integrity.
5. Explain the GROUP BY clause and give an example.
Answer:
The GROUP BY clause allows you to group rows with the same values in specified columns into summary rows. It is commonly used with aggregate functions such as COUNT, SUM, AVG, MAX, MIN.
Example:
SELECT department, COUNT(*)
FROM employees
GROUP BY department;
This query will return the number of employees in each department.
6. What is the difference between WHERE and HAVING clauses?
Answer:
- WHERE: Filter rows before grouping.
- HAVING: Filter rows after grouping (used with aggregate functions).
Example:
SELECT department, COUNT(*)
FROM employees
GROUP BY department
HAVING COUNT(*) > 5;
This question organizations the personnel via way of means of branch and returns simplest the ones departments which have extra than five personnel.
7. What is a subquery?
Answer:
A subquery is a question inside every other question. It may be used withinside the SELECT, INSERT, UPDATE, or DELETE statements. Subqueries may be used to go back a unmarried value (scalar subquery) or more than one rows (desk subquery).
Example:
SELECT name
FROM employees
WHERE emp_id = (SELECT emp_id FROM salaries WHERE salary > 50000);
8. What are indexes and why are they used?
Answer:
An index is a database object that improves the speed of data retrieval operations on a table at the cost of additional space and maintenance time. An index allows the database engine to quickly locate rows based on indexed columns.
Example:
CREATE INDEX idx_employee_name ON employees(name);
9. What is normalization?
Answer:
Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. It involves dividing the database into smaller, linked tables and ensuring that each table contains data associated with a single entity. There are several normal forms, ranging from 1NF (First Normal Form) to 5NF (Fifth Normal Form).
10. What is denormalization?
Answer:
Denormalization is the process of combining tables and reducing the level of normalization to improve read performance by reducing the number of joins. Although denormalization increases redundancy, it can speed up query execution for certain types of queries.
11. What is a view in SQL?
Answer:
A view is a virtual table that contains a stored query. It does not store data itself but displays data from one or more tables. Views can simplify complex queries and users can interact with views as if they were regular tables.
Example:
CREATE VIEW employee_details AS
SELECT emp_id, name, department
FROM employees;
12. What is the difference between UNION and UNION ALL?
Answer:
- UNION: Combines result sets from two or more queries and removes duplicate rows.
- UNION ALL: Combines result sets from two or more queries but does not remove duplicates.
Example:
SELECT name FROM employees
UNION
SELECT name FROM contractors;
SELECT name FROM employees
UNION ALL
SELECT name FROM contractors;
13. What is a transaction in SQL and how is it managed?
Answer:
A transaction is a sequence of SQL operations executed as a single unit. Transactions ensure data integrity and complete successfully (commit) or fail (rollback).
SQL Command:
- START TRANSACTION: Starts a transaction.
- COMMIT: Commits the transaction, making the changes permanent.
- ROLLBACK: Rollback the transaction, rolling back the changes.
Example:
BEGIN TRANSACTION;
UPDATE accounts SET balance = balance - 100 WHERE account_id = 1;
UPDATE accounts SET balance = balance + 100 WHERE account_id = 2;
COMMIT;
14. What is the DISTINCT keyword used for?
- Answer: The
DISTINCTkeyword is used to remove duplicate rows from the result set of a query.
Example:
SELECT DISTINCT department
FROM employees;
15. How can you find the second highest salary in a table?
- Answer:
SELECT MAX(salary) AS second_highest_salary
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);
Alternatively, using ROW_NUMBER():
WITH RankedSalaries AS (
SELECT salary, ROW_NUMBER() OVER (ORDER BY salary DESC) AS rank
FROM employees
)
SELECT salary FROM RankedSalaries WHERE rank = 2;
These are some basic SQL questions you may encounter in an HSBC interview. To prepare well, focus on getting a deep understanding of SQL concepts, including joins, normalization, subqueries, and optimization techniques.
Preparation tips
Be prepared to write SQL queries on a whiteboard or code board. Understand the SQL functions and commands specific to the RDBMS you are working with (e.g. SQL Server, Oracle, MySQL, PostgreSQL). Practice on Entri App to perfect your SQL skills. By preparing for these types of questions, you’ll be ready to demonstrate your technical knowledge in your HSBC SQL interview.
