SQL | The INSERT INTO AND UPDATE Statement

• The INSERT INTO statement is used to insert new records in a table.
• The INSERT INTO statement is used to insert a new row in a table.
• SQL INSERT INTO Syntax
• It is possible to write the INSERT INTO statement in two forms.
• The first form doesn’t specify the column names where the data will be inserted, only their values:

INSERT INTO table_name VALUES (value1, value2, value3,...)

The second form specifies both the column names and the values to be inserted:

INSERT INTO table_name (column1, column2, column3,...) VALUES (value1, value2,
value3,...)

SQL INSERT INTO Example

We have the following “Persons” table:

Now we want to insert a new row in the “Persons” table.
We use the following SQL statement:

INSERT INTO Persons VALUES (4,'Nilsen', 'Johan', 'Bakken 2', 'Stavanger')

The “Persons” table will now look like this:

Insert Data Only in Specified Columns

It is also possible to only add data in specific columns.
The following SQL statement will add a new row, but only add data in the “P_Id”, “LastName” and the
“FirstName” columns:

INSERT INTO Persons (P_Id, LastName, FirstName) VALUES (5, 'Tjessem', 'Jakob')

The “Persons” table will now look like this:

The UPDATE Statement

• The UPDATE statement is used to update records in a table.
• The UPDATE statement is used to update existing records in a table.
• SQL UPDATE Syntax:

UPDATE table_name
SET column1=value, column2=value2,...
WHERE some_column=some_value

Note: Notice the WHERE clause in the UPDATE syntax. The WHERE clause specifies which record or
records that should be updated. If you omit the WHERE clause, all records will be updated!

SQL UPDATE Example

The “Persons” table:

Now we want to update the person “Tjessem, Jakob” in the “Persons” table.
We use the following SQL statement:

UPDATE Persons
SET Address='Nissestien 67', City='Sandnes'
WHERE LastName='Tjessem' AND FirstName='Jakob'

The “Persons” table will now look like this:

SQL UPDATE Warning

Be careful when updating records. If we had omitted the WHERE clause in the example above, like this:

UPDATE Persons
SET Address='Nissestien 67', City='Sandnes'

The “Persons” table would have looked like this: