T-SQL Update Statement

The T-SQL UPDATE statement is used to modify the existing records in the database.

We use the WHERE clause with the UPDATE query to update the particular rows. Otherwise, all rows would be affected.

Syntax of UPDATE query with WHERE clause is given below:

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

We combine N number of conditions by using the AND or OR operators.

See the EMPLOYEES table having the following records –

ID	Name	AGE	ADDRESS	Salary
001	Rahul	23	Kota	22000.00
002	Clinton	22	Mumbai	15000.00
003	Kamal	31	Delhi	25000.00
004	Chitra	28	Kanyakumari	65000.00
005	Santanu	26	Madhya Pradesh	38500.00
006	Savitri	24	Bhopal	4500.00
007	Manii	30	Indonesia	15000.00

The below command is an example, which would update ADDRESS for a customer whose ID is 6 ?

EMPLOYEES table will now have the following records ?

ID	Name	AGE	ADDRESS	Salary
001	Rahul	23	Kota	22000.00
002	Clinton	22	Mumbai	15000.00
003	Kamal	31	Delhi	25000.00
004	Chitra	28	Kanyakumari65000.00
005	Santanu	26	Madhya Pradesh	38500.00
006	Savitri	24	Pune	4500.00
007	Manii	30	Indonesia	15000.00

If we want to modify all ADDRESS and SALARY columns in the EMPLOYEES table, we have to use the WHERE clause. UPDATE query is given as follows –

EMPLOYEES table will have the below records.

ID	Name	AGE	ADDRESS	Salary
001	Rahul	23	Kota	22000.00
002	Clinton	22	Mumbai	15000.00
003	Kamal	31	Delhi	25000.00
004	Chitra	28	Kanyakumari	65000.00
005	Santanu	26	Madhya Pradesh	38500.00
006	Savitri	24	Bhopal	4500.00
007	Manii	30	Goa	15000.00