ZS Business Technology Analyst Interview Questions and Answers

SQL joins combine rows from two or more tables based on related columns.

• INNER JOIN: Returns records with matching values in both tables. Example: SELECT * FROM A INNER JOIN B ON A.id = B.a_id;

• LEFT JOIN: Returns all records from the left table and matched records from the right table. Example: SELECT * FROM A LEFT JOIN B ON A.id = B.a_id;

• RIGHT JOIN: Returns all records from the right table and matched records from ...read more

Design a database for a startup to increase revenue.

• Identify key business processes and data requirements

• Design a relational database schema to store the necessary data

• Optimize the database structure for efficient querying and data retrieval

• Implement data validation and integrity constraints

• Consider scalability and future growth

• Leverage data analytics and business intelligence tools for revenue optimization

SQL can be utilized in various business scenarios to analyze data and derive insights for decision-making.

• Data Analysis: Use SQL to query sales data to identify trends over time, e.g., SELECT AVG(sales) FROM sales_data WHERE date BETWEEN '2023-01-01' AND '2023-12-31'.

• Customer Segmentation: SQL can help segment customers based on purchase behavior, e.g., SELECT customer_id, COUNT(order_id) FROM orders GROUP BY cust...read more

Fact and dimensions are components of a data warehouse. Facts are numerical data while dimensions are descriptive data.

• Facts are quantitative data that can be measured, such as sales revenue or number of customers.

• Dimensions are descriptive data that provide context for the facts, such as time, location, or product.

• Facts and dimensions are stored in a data warehouse, which is a large repository of data used for an...read more

SCD stands for Slowly Changing Dimensions. It is a technique used in data warehousing to track changes in data over time.

• Type 1 SCD: Overwrite the old data with new data. Example: Customer address change.

• Type 2 SCD: Create a new record for the change. Example: Employee promotion.

• Type 3 SCD: Create a new attribute to store the change. Example: Product price change.

• Type 4 SCD: Create a separate table to store the ch...read more

The problem involves outputting elements of a 2D matrix in diagonal order, alternating directions.

• Iterate through the matrix diagonally, starting from the top-left element.

• Alternate the direction of traversal from bottom-left to top-right and vice versa.

• Handle large matrices efficiently by taking advantage of matrix properties.

• Example: For a 3x3 matrix [1, 2, 3, 4, 5, 6, 7, 8, 9], the output should be 1 2 4 7 5 3 ...read more