SQL UPDATE

--update a single value in the given row

UPDATE Customers
SET age = 21
WHERE customer_id = 1;

SQL UPDATE TABLE Syntax

UPDATE table_name
SET column1 = value1, column2 = value2, ...
[WHERE condition];

Here,

• table_name is the name of the table to be modified
• column1, column2, ... are the names of the columns to be modified
• value1, value2, ... are the values to be set to the respective columns
• [WHERE condition] is an optional clause specifying which rows should be updated

Update a Single Value in a Row

In SQL, we can update a single value by using the UPDATE command with a WHERE clause. For example,

-- update a single value in the given row

UPDATE Customers
SET first_name = 'Johnny'
WHERE customer_id = 1;

Here, the SQL command changes the value of the first_name column to Johnny if customer_id is equal to 1.

Update Multiple Values in a Row

We can also update multiple values in a single row at once. For example,

-- update multiple values in the given row

UPDATE Customers
SET first_name = 'Johnny', last_name = 'Depp'
WHERE customer_id = 1;

Here, the SQL command changes the value of the first_name column to Johnny and last_name to Depp if customer_id is equal to 1.

Update Multiple Rows

We use the UPDATE statement to update multiple rows at once. For example,

-- update multiple rows satisfying the condition

UPDATE Customers
SET country = 'NP'
WHERE age = 22;

Here, the SQL command changes the value of the country column to NP if age is 22.

If there is more than one row where age equals to 22, all the matching rows will be modified.

Update all Rows

We can update all the rows in a table at once by omitting the WHERE clause. For example,

-- update all rows

UPDATE Customers
SET country = 'NP';

Here, the SQL command changes the value of the country column to NP for all rows.

Note: We should be cautious while using the UPDATE statement. If we omit the WHERE clause, all the rows will be changed, and this change is irreversible.

Also Read:

• SQL INSERT INTO SELECT
• SQL INSERT INTO
• SQL SELECT INTO