![]() ![]() If the Name is not present in any branch the Br_name field we get for that Name is NULL. In this query, the first left join gets all the rows with the names of students from the S t u d e n t Student S t u d e n t table along with all the Br_name. Let's take an example to understand this.Įxample: Obtain all the names of the students even if they are not present in any City and Branch. When we use left join on the multiple tables, it will include all the rows from the left table, that is the table mentioned on the left side of the join and the next left joins will be applied to the result of the first left join. Note: A virtual table is a table that is created in memory, when we join three tables, the result from joining the first two tables is stored in a virtual table, and when the second join is applied, it is applied on the virtual table. Here, we first INNER JOIN two tables, Branch and Student, using Br_id, then another INNER JOIN added to the output of the first two tables using city_id. The first join creates the virtual table, which has data from the first two tables, and then the second JOIN condition is applied to that virtual table. So to retrieve data from more than two tables, we need to use the JOIN condition multiple times. The Student table contains Stud_id as the primary key, Name, Br_id as the foreign key referring Branch table, Email and City_id as the foreign key referring Address table. Let us assume that there are three tables in our database Student, Branch, and Address. Data can be retrieved using different types of joins like INNER JOIN, LEFT JOIN, or both based on different requirements. This can be accomplished using a multiple-table join. We often need to get data from three or more tables to get meaningful information. You can refer to this article on Scaler Topics for more information. ![]() Introduction Note: Ensure that you are familiar with SQL Joins before continuing. In SQL, joining multiple tables means you can join n n n number of tables, but, to join n n n number of tables, the joins required are n − 1 n-1 n − 1, that is for 3 3 3 tables, 2 2 2 joins are required. The join operator is used multiple times to join multiple tables in SQL, as for each new table, one join is added. We use multiple tables joins to combine data from more than two tables. ![]()
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