The SQL UPDATE Query is used to modify the existing records in a table. You can use the WHERE clause with the UPDATE query to update the selected rows, otherwise all the rows would be affected.
Syntax
The basic syntax of the UPDATE query with a WHERE clause is as follows −
UPDATE table_name SET column1 = value1, column2 = value2...., columnN = valueN WHERE [condition];
You can combine N number of conditions using the AND or the 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 | +----+----------+-----+-----------+----------+
The following query will update the ADDRESS for a customer whose ID number is 6 in the table.
SQL> UPDATE CUSTOMERS SET ADDRESS = 'Pune' WHERE ID = 6;
Now, the CUSTOMERS table would 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 the ADDRESS and the SALARY column values in the CUSTOMERS table, you do not need to use the WHERE clause as the UPDATE query would be enough as shown in the following code block.
SQL> UPDATE CUSTOMERS SET ADDRESS = 'Pune', SALARY = 1000.00;
Now, CUSTOMERS table would 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 | +----+----------+-----+---------+---------+
