> For the complete documentation index, see [llms.txt](https://docs.cascade.io/cascade/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cascade.io/cascade/cascade-faqs/knowledge-based/understanding-the-join-options-in-the-cascade-join-tool.md). # Understanding the Join options in the Cascade Join tool The [Join](/cascade/tools/combine/join.md) tool in Cascade is a powerful and handy way to do simple and complex joins. To new users, the join choices might seem confusing. Nonetheless, grasping the different types of joins and when to use them is not hard. ## 😇 Inner Join An inner join combines records from two or more tables in a relational database based on a shared field between them. This is the most common kind of join, and it will return all rows from both tables where the join condition is met. For example, an analyst might use an inner join to combine customer and order tables to figure out which customers have placed orders. The join condition would be the user ID field. ## 🚀 Outer Join An outer join is a type of join that retrieves all rows from one table, even if there is no corresponding row in the other table. There are three types of outer joins: left, right, and full outer join. For instance, an analyst might use an outer join to combine customer and order tables to find out which customers have not placed orders. The join condition would be the user ID field. ## ◀️ Left Join A left join is a type of outer join that yields all rows from the left table, even if there is no related row in the right table. It will also return any rows from the right table where the join condition is met. For example, an analyst might employ a left join to combine customer and order tables to determine which customers have placed orders and which customers have not placed orders. The join condition would be the user ID field. ## ▶️ Right Join A right join is a type of outer join that yields all rows from the right table, even if there is no related row in the left table. It will also return any rows from the left table where the join condition is fulfilled. For example, an analyst might use a right join to combine customer and order tables to find out which orders have been placed by customers and which orders have not been placed by customers. The join condition would be the user ID field. ## 🤞 Cross Join A cross join is a type of join that combines every row from one table with every row from another table. It is also referred to as a Cartesian join. The result of a cross join can be quite large and should be used with caution. For example, an analyst might employ a cross join to combine customer and product tables to determine which customers have purchased which products. The join condition would be the product ID field. ## 🙏 More Help The [Join](/cascade/tools/combine/join.md) tool in Cascade makes it easy and efficient for users to guarantee and validate consistency and accuracy through automated joins. It is the perfect solution for performing joins in Cascade, allowing users to quickly and reliably access the data they need. ### Other Sources {% content-ref url="/pages/-MYR53LZav2IXstYpCav" %} [Join](/cascade/tools/combine/join.md) {% endcontent-ref %} {% content-ref url="/pages/QAEVSsqHuRBL5SC4ZaPP" %} [Multi Join](/cascade/tools/combine/multijoin.md) {% endcontent-ref %} --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.cascade.io/cascade/cascade-faqs/knowledge-based/understanding-the-join-options-in-the-cascade-join-tool.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.