Tata Technologies Data Analyst Interview Questions and Answers

Joins are used to combine rows from two or more tables based on a related column between them.

• Types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• INNER JOIN returns rows when there is at least one 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 ...read more

Aggregate functions are functions in databases that perform a calculation on a set of values and return a single value.

• Aggregate functions are used to perform operations on a group of rows and return a single result.

• Common aggregate functions include SUM, AVG, COUNT, MIN, and MAX.

• For example, SUM function calculates the total of a column, AVG calculates the average, COUNT counts the number of rows, MIN finds the minimu

A decision tree is a flowchart-like structure in which each internal node represents a test on an attribute, each branch represents the outcome of the test, and each leaf node represents a class label.

• Decision trees are a popular machine learning algorithm used for classification and regression tasks.

• They are easy to interpret and visualize, making them useful for understanding the decision-making process.

• Each internal...read more

Model evaluation metrics are used to assess the performance of machine learning models.

• Model evaluation metrics help in determining how well a model is performing in terms of accuracy, precision, recall, F1 score, etc.

• Common evaluation metrics include accuracy, precision, recall, F1 score, ROC-AUC, confusion matrix, and mean squared error.

• These metrics help in comparing different models and selecting the best one for a...read more