The table-name specifies the name of the table to update. Only a single table is allowed.
An identifier to use when referencing the table from elsewhere in the statement.
Each named column is set to the value of the expression on the right-hand side of the equal sign. There are no restrictions
on the expression. If the expression is a column-name, the old value is used.
Only columns specified in the SET clause have their values changed. In particular, you cannot use UPDATE to set a column's
value to its default.