Impelsys Data Analyst Interview Questions and Answers

Distinct returns unique values while group by groups and aggregates data based on a column.

• Distinct returns only unique values from a single column.

• Group by groups and aggregates data based on a column.

• Distinct can be used to count the number of unique values in a column.

• Group by can be used to group data by a column and perform aggregate functions like sum, count, avg, etc.

• Distinct is used to remove duplicates from a ...read more

Right join and right outer join are the same thing.

• Right join and right outer join are interchangeable terms.

• Both return all the rows from the right table and matching rows from the left table.

• If there is no match, the result will contain NULL values for the left table columns.

• Used to combine data from two tables based on a common column.

• Syntax: SELECT * FROM table1 RIGHT JOIN table2 ON table1.column = table2.column;

Special characters in columns can be handled by replacing or removing them.

• Identify the special characters in the column

• Replace the special characters with a suitable alternative

• Remove the special characters if they are not necessary

• Use regular expressions to handle complex special characters

• Ensure that the data type of the column is appropriate