The SQL Server UPDATE Query is used to modify the existing records in a table.

You can use WHERE clause with UPDATE query to update selected rows otherwise all the rows would be affected.

Syntax

Following is the basic syntax of UPDATE query with WHERE clause −

UPDATE table_name 
SET column1 = value1, column2 = value2...., columnN = valueN 
WHERE [condition];

You can combine N number of conditions using AND or OR operators.

Example

Consider the CUSTOMERS table having the following records −

ID  NAME       AGE       ADDRESS             SALARY 
1   Ramesh     32        Ahmedabad           2000.00 
2   Khilan     25        Delhi               1500.00 
3   kaushik    23        Kota                2000.00 
4   Chaitali   25        Mumbai              6500.00 
5   Hardik     27        Bhopal              8500.00 
6   Komal      22        MP                  4500.00 
7   Muffy      24        Indore              10000.00 

Following command is an example, which would update ADDRESS for a customer whose ID is 6 −

UPDATE CUSTOMERS 
SET ADDRESS = ''Pune'' 
WHERE ID = 6; 

CUSTOMERS table will now have the following records −

ID  NAME       AGE       ADDRESS             SALARY 
1   Ramesh     32        Ahmedabad           2000.00 
2   Khilan     25        Delhi               1500.00 
3   kaushik    23        Kota                2000.00 
4   Chaitali   25        Mumbai              6500.00 
5   Hardik     27        Bhopal              8500.00 
6   Komal      22        Pune                4500.00 
7   Muffy      24        Indore              10000.00 

If you want to modify all ADDRESS and SALARY column values in CUSTOMERS table, you do not need to use WHERE clause. UPDATE query would be as follows −

UPDATE CUSTOMERS 
SET ADDRESS = ''Pune'', SALARY = 1000.00;

CUSTOMERS table will now have the following records.

ID  NAME       AGE       ADDRESS          SALARY 
1   Ramesh     32        Pune             1000.00 
2   Khilan     25        Pune             1000.00 
3   kaushik    23        Pune             1000.00 
4   Chaitali   25        Pune             1000.00 
5   Hardik     27        Pune             1000.00 
6   Komal      22        Pune             1000.00 
7   Muffy      24        Pune             1000.00