TCS Data Engineer Interview Questions, Process, and Tips

Use SQL query to select unique customers in last 3 months sales

• Filter sales data for the last 3 months

• Use DISTINCT keyword to select unique customers

• Join with customer table if necessary

Data mining is the process of analyzing large datasets to discover patterns, trends, and insights.

• Data mining involves extracting useful information from large datasets

• It uses techniques such as machine learning, statistics, and database systems

• Examples include market basket analysis, anomaly detection, and clustering

Data can be transformed into useful data through Python by cleaning, transforming, and analyzing it.

• Clean the data by removing duplicates, handling missing values, and correcting errors.

• Transform the data by reshaping it, aggregating it, or creating new features.

• Analyze the data by performing statistical analysis, machine learning algorithms, or data visualization.

• Example: Use pandas library to clean and transform data...read more

In Python, a tree is a hierarchical data structure composed of nodes connected by edges.

• Trees are used to represent hierarchical relationships, such as file systems or organization charts.

• Each node in a tree has a parent node and zero or more child nodes.

• Trees can be binary (each node has at most two children) or n-ary (each node can have multiple children).

• Example: Binary tree implementation in Python using classes an