PostgreSQL UPDATE
The UPDATE Statement
The UPDATE statement is used to modify the value(s) in existing records in a table.
Example
Set the color of the Volvo to 'red':
UPDATE cars
SET color = 'red'
WHERE brand = 'Volvo';
Result
UPDATE 1
Which means that 1 row was affected by the UPDATE statement.
Note: Be careful with the WHERE clause,
in the example above ALL rows where brand = 'Volvo' gets updated.
Display Table
To check the result we can display the table with this SQL statement:
Warning! Remember WHERE
Be careful when updating records. If you omit the WHERE clause,
ALL records will be updated!
Example
Without the WHERE clause, ALL records will be updated:
UPDATE cars
SET color = 'red';
Result
UPDATE 4
Which means that all 4 row was affected by the UPDATE statement.
Display Table
To check the result we can display the table with this SQL statement:
Update Multiple Columns
To update more than one column, separate the name/value pairs with a comma ,:
Example
Update color and year for the Toyota:
UPDATE cars
SET color = 'white', year = 1970
WHERE brand = 'Toyota';
Result
UPDATE 1
Which means that 1 row was affected by the UPDATE statement.
Display Table
To check the result we can display the table with this SQL statement:
