UPDATE
Updating a table based on joining another table
Section titled “Updating a table based on joining another table”You can also update data in a table based on data from another table:
UPDATE personSET state_code = cities.state_codeFROM citiesWHERE cities.city = city;Here we are joining the person city column to the cities city column in order to get the city’s state code. This is then used to update the state_code column in the person table.
Update all rows in a table
Section titled “Update all rows in a table”You update all rows in table by simply providing a column_name = value:
UPDATE person SET planet = 'Earth';Update all rows meeting a condition
Section titled “Update all rows meeting a condition”UPDATE person SET state = 'NY' WHERE city = 'New York';Updating multiple columns in table
Section titled “Updating multiple columns in table”You can update multiple columns in a table in the same statement, separating col=val pairs with commas:
UPDATE person SET country = 'USA', state = 'NY'WHERE city = 'New York';