PwC Data Analyst Interview Questions and Answers

The main difference between 'having' and 'where' in SQL is that 'having' is used with aggregate functions to filter groups, while 'where' is used to filter rows.

• HAVING is used with GROUP BY to filter groups based on aggregate functions results

• WHERE is used to filter rows based on conditions

• HAVING is applied after GROUP BY, while WHERE is applied before GROUP BY

• Example: SELECT department, AVG(salary) FROM employees...read more

Different types of joins in SQL are inner join, left join, right join, and full outer 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 outer join: Returns rows when there is a match in either table

Compare record count of 2 score files and print if they are equal or not.

• Read both score files

• Count the number of records in each file

• Compare the record counts

• Print if they are equal or not

Query to generate state-wise sales summary report with ranking using multiple table joins.

• Use SQL JOINs to combine sales, states, and products tables.

• Aggregate sales data using SUM() function grouped by state.

• Use RANK() or DENSE_RANK() to rank states based on total sales.

• Example SQL: SELECT state, SUM(sales) AS total_sales, RANK() OVER (ORDER BY SUM(sales) DESC) AS sales_rank FROM sales_data JOIN states ON sales_d...read more

Query to retrieve all customer names starting with A.

• Use the SELECT statement to retrieve customer names.

• Use the LIKE operator with the pattern 'A%' to match names starting with A.

• Specify the table and column name where the customer names are stored.

• Example: SELECT customer_name FROM customers WHERE customer_name LIKE 'A%';

Substring is a part of a string that is smaller in length and extracted from the original string.

• Substring is a sequence of characters within a string.

• It can be extracted using string slicing or substring functions.

• For example, 'hello world'[0:5] will return 'hello'.

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization involves breaking down a database into smaller, more manageable tables

• Each table should have a primary key that uniquely identifies each record

• Data is then organized into related tables to minimize redundancy

• Normalization helps to prevent data inconsistencies and anomalies

• There are different ...read more

SQL has four types of joins: Inner Join, Left Join, Right Join, and Full Outer Join.

• Inner Join returns only the matching rows from both tables.

• Left Join returns all the rows from the left table and matching rows from the right table.

• Right Join returns all the rows from the right table and matching rows from the left table.

• Full Outer Join returns all the rows from both tables, with NULL values in the columns where ...read more