SQL SERVER : update command

The SQL UPDATE general syntax looks like this:
UPDATE Table1

SET Column1 = Value1, Column2 = Value2

WHERE Some_Column = Some_Value
Database: Adventure Works
Schema: Person
Table: Address
Example:

Update Address

set AddressLine1 ='123 – jkv road'

Where AddressID = 10

The SQL UPDATE clause changes the data in already existing database row(s) and usually we need to add a conditional SQL WHERE clause to our SQL UPDATE statement in order to specify which row(s) we intend to update.

If we don’t specify a WHERE clause in the SQL expression above, all Address AddressLine1 will be updated to '123 – jkv road', so be careful with the SQL UPDATE command when you use.

We can update several database table rows at once, by using the SQL WHERE clause in our UPDATE statement. For example if we want to change the PostalCode for all Address with City  'Bothell' (we have 2 in our example Address table), we need to use the following SQL UPDATE statement:
Update Address set PostalCode = 98011 Where City  = 'Bothell'