When working with databases, one of the most common tasks is inserting new records into a table. This can be done using an INSERT statement in SQL Server. However, there may be instances where you need to retrieve the unique identifier, or "id," of the record that was just inserted. In this article, we will explore how to get the "id" of a record upon execution of an INSERT statement in SQL Server.
First, let's set the stage with a simple scenario. Imagine you have a table called "Customers" that stores information about your customers, such as their name, address, and phone number. This table has an "id" column that serves as the unique identifier for each customer. Now, let's say you want to insert a new customer into this table and retrieve their "id" for future use.
To achieve this, we will use the OUTPUT clause in our INSERT statement. This clause allows us to return data from the inserted rows, including the newly generated "id" value. Let's take a look at the syntax of an INSERT statement with the OUTPUT clause:
INSERT INTO Customers (Name, Address, Phone)
OUTPUT INSERTED.id
VALUES ('John Doe', '123 Main St', '555-1234')
In this example, we are inserting a new customer with the name "John Doe," address "123 Main St," and phone number "555-1234." The OUTPUT clause instructs SQL Server to return the "id" value of the inserted row. This value will be stored in a temporary table called "INSERTED," which we can then query to retrieve the "id."
Now, you may be wondering why we need to use the OUTPUT clause instead of simply querying the table after the INSERT statement. The reason is that the OUTPUT clause allows us to retrieve the "id" of the specific record that was just inserted, even if multiple rows were inserted in the same statement. This is especially useful when inserting records in bulk.
Let's see an example of how to retrieve the "id" using the OUTPUT clause when inserting multiple records:
INSERT INTO Customers (Name, Address, Phone)
OUTPUT INSERTED.id
VALUES ('Jane Smith', '456 Oak St', '555-4321'),
('Bob Johnson', '789 Pine St', '555-9876')
Here, we are inserting two new customers at once. The OUTPUT clause will return both "id" values in the temporary table, which we can then query to retrieve the "id" of each record.
Another approach to getting the "id" of a record upon execution of an INSERT statement is by using the SCOPE_IDENTITY() function. This function returns the last identity value inserted into an identity column in the same scope. Let's take a look at an example:
INSERT INTO Customers (Name, Address, Phone)
VALUES ('Sarah Williams', '890 Maple St', '555-5678')
SELECT SCOPE_IDENTITY() AS 'InsertedId'
In this example, we are inserting a new customer and immediately selecting the "id" value using the SCOPE_IDENTITY() function. This approach can also be useful when performing bulk inserts, as it will return the "id" value of the last inserted record.
In conclusion, retrieving the "id" of a record upon execution of an INSERT statement can be achieved using the OUTPUT clause or the SCOPE_IDENTITY() function. Both approaches are valid and can be used depending on your specific scenario. By using these techniques, you can easily retrieve the unique identifier of a record and continue working with it in your database.
