SQL UPDATE Statement

The UPDATE statement is used to update records in a table.


The UPDATE Statement

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:

P_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes
2SvendsonToveBorgvn 23Sandnes
3PettersenKariStorgt 20Stavanger
4NilsenJohanBakken 2Stavanger
5TjessemJakob

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:

P_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes
2SvendsonToveBorgvn 23Sandnes
3PettersenKariStorgt 20Stavanger
4NilsenJohanBakken 2Stavanger
5TjessemJakobNissestien 67Sandnes


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:

P_IdLastNameFirstNameAddressCity
1HansenOlaNissestien 67Sandnes
2SvendsonToveNissestien 67Sandnes
3PettersenKariNissestien 67Sandnes
4NilsenJohanNissestien 67Sandnes
5TjessemJakobNissestien 67Sandnes

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