Thus, we can execute the product and selection process on two tables using a single join statement. We can use either 'on' or 'using' clause in MySQL to apply predicates to the join queries. For all the examples, we will consider the below-mentioned employee and department table. Inner Join is a join that can be used to return all the values that have matching values in both the tables.
Inner Join can be depicted using the below diagram. The inner join can be further divided into the following types:. Equi Join is an inner join that uses the equivalence condition for fetching the values of two tables. Natural Join is an inner join that returns the values of the two tables on the basis of a common attribute that has the same name and domain. It does not use any comparison operator. It also removes the duplicate attribute from the results. The above query will return the values of tables removing the duplicates.
If we want to specify the attribute names, the query will be as follows:. Outer Join is a join that can be used to return the records in both the tables whether it has matching records in both the tables or not. The outer join can be further divided into three types:. Now we have a new member who has not rented any movie yet. Skip to content. It is the most widely used join operation and can be considered as a default join-type An Inner join or equijoin is a comparator-based join which uses equality comparisons in the join-predicate.
Report a Bug. Previous Prev. Next Continue. Home Testing Expand child menu Expand. SAP Expand child menu Expand. Web Expand child menu Expand. The SQL multiple joins approach will help us to join onlinecustomers , orders, and sales tables.
As shown in the Venn diagram, we need to matched rows of all tables. For this reason, we will combine all tables with an inner join clause. The following query will return a result set that is desired from us and will answer the question:. At first, we will analyze the query. An inner join clause that is between onlinecustomers and orders tables derived the matched rows between these two tables.
The second inner join clause that combines the sales table derived the matched rows from the previous result set. The following colored tables illustration will help us to understand the joined tables data matching in the query.
The yellow-colored rows specify matched data between onlinecustomers and orders. On the other hand, only the blue colored rows exist in the sales tables so the query result will be blue colored rows:. We can use the different types of joins in a single query so that we can overcome different relational database issues.
In this example, we need all rows of the orders table, which are matched to onlinecustomers tables. On the other hand, these rows do not exist in the sales table. The grey-colored area indicates rows which will be the output of the query:. In the first step, we should combine the onlinecustomers and orders tables through the inner join clause because inner join returns all the matched rows between onlinecustomers and orders tables.
In the second step, we will combine the orders table to the sales table through the left join and then filter the null values because we need to eliminate the rows which are stored by the sales table:.
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