The UPDATE SET syntax is used to modify the data in the update data table.
UPDATE tb_name SET column1 = new_value1, column2 = new_value2, ... WHERE conditions
This syntax updates the value of column1 in the records that match the WHERE condition in the data table to new_value1, the value of column2 to new_value2, and so on. If the WHERE condition is omitted, the column values for all the records in the table are updated.
UPDATE user SET email = 'firstname.lastname@example.org' WHERE uid = 3
The UPDATE syntax allows SETs to be followed by an expression.
UPDATE article SET page_view = page_view + 1 WHERE id = 123
This example allows an article with an page_view of 123 to be incremented by 1 when it is clicked to read.
UPDATE persondata SET age = age * 2, age = age + 1
The example SET is followed by two expressions: age = age * 2 (age doubled), age = age + 1 (plus 1). In the case of such multiple expressions, they are executed from left to right.