SQL UPDATE Query - SQL UPDATE Statement

Introduction to Update Query in SQL

The update command is a DML command that works on the records of a particular database table. The primary function of the update query in SQL is to update single or multiple records of the table.

Let's understand the syntax for updating queries in SQL.

Syntax for Update in SQL

The update command takes tableName and a set keyword for updating the table's records. We can also use the while clause in the update command. That's why we can update multiple records at the same time.

Syntax:

SQL UPDATE Statement Examples

You may want to update a particular student's name in the table. You have two options: delete the old record from the table and insert the updated record, but there are more efficient approaches. We will take the update query to update the name of the student.

Consider the table below.

TableName: Student

Updating Name of the Student

Let's say you want to change the name of the student Amit to Amit Sharma. To update the record, we will use the update query.

Let's understand how to update the name

Syntax

We will take the help of the AdminNo to fetch the desired record from the table. Because the AdminNo is unique, the update command will fetch only a single record if it is present.

Check out this SQL Tutorial to learn more about SQL in depth.

UPDATE One Column

Updating one column means changing the value of a particular column for specific or multiple records.

Let's understand how to update one column using the update DML command.

Consider the below table.

TableName: Student

Updating Name of the Student

Suppose you want to change the name of the student Sourav to Sourav Sharma. To update the record, we will use the update query.

Let's understand how to update the name

Syntax

We will take the help of the AdminNo to fetch the desired record from the table. Because the AdminNo is unique, the update command will fetch only a single record if it is present.

UPDATE Multiple Columns

Updating multiple columns means changing the value of multiple columns for specific or multiple records.

Let's understand how to update multiple columns using the update DML command.

Consider the below table.

TableName: Student

Updating Name of the Student

You want to change the name of the student Sourav to Sourav Sharma as well as update the marks of the student. To perform this task, we will use the update query.

To update the name and marks, we can use the following query:

UPDATE Multiple Rows

We can update the multiple rows of the table using the single update command. Let's understand how to update the multiple rows of the table.

Consider the below table:

TableName: Student

If we want to update the class of all the records that belong to class 5 to class 6, we can use the following query:

The above query will update the first two rows of the student table.