Difference between Function and Stored Procedure in SQL Server

In this post, I will explain the difference between Function and Stored Procedure in SQL Server.

A stored procedure is a group of SQL statements that have been created and stored in the database. A stored procedure will accept input parameters so that a single procedure can be used over the network by several clients using different input data. If we modify a stored procedure all the clients will get the updated stored procedure.

A function is a database object in SQL Server. Basically, it is a set of SQL statements that accepts only input parameters, perform actions and return the result. A function can return only a single value or a table. We can’t use a function to Insert, Update, Delete records in the database table(s).

Difference between Function and Stored Procedure 

1. A Function must return a value but in Stored Procedure it is optional ( Procedure can return zero or n values).
2. Functions can have only input parameters for it whereas Procedures can have input/output parameters.
3. Functions can be called from Procedure whereas Procedures cannot be called from Function.
4. The procedure allows SELECT as well as DML (INSERT/UPDATE/DELETE) statement in it whereas Function allows only SELECT statement in it.
5. Procedures can not be utilized in a SELECT statement whereas Function can be embedded in a SELECT statement.
6. Stored Procedures cannot be used in the SQL statements anywhere in the WHERE/HAVING/SELECT section whereas Function can be.
7. Functions that return tables can be treated as another row set. This can be used in JOINs with other tables.
8. Inline Function can be thought of as views that take parameters and can be used in JOINs and another Row set operations.
9. An exception can be handled by try-catch block in a procedure whereas try-catch block cannot be used in a Function.
10. We can go for Transaction Management in Procedure whereas we can't go in Function.