Differentiate between Tabular, Summary,Matrix and Joined Reports in Salesforce.

Tabular Reports:- These kind of reports are used when the requirement is just to view the data.
Summary Reports:- Summary reports are similar to tabular reports, but also allow users to group rows of data, view subtotals, and create charts. They can be used as the source report for dashboard components.
Matrix Reports:- allow you to group and summarize data by both rows and columns. They can be used as the source report for dashboard components.
Joined Reports:- Joined reports let you create multiple report blocks that provide different views of your data.