Difference between procedure and function ?

1. Functions are compiled and executed at run time.
Stored procedures are stored in parsed and compiled format in the database.

2. Functions cannot affect the state of the database which means we cannot perform insert,delete,update and create operations on the database.
Stored Procedures can affect the state of the database by using insert,delete,update and create operations.

3 Functions are basically used to compute values. We passes some parameters to functions as input and then it performs some operations on the parameter and return output.
Stored procedures are basically used to process the task.

4.Function can not change server environment and our operating system environment.
Stored procedures can change server environment and our operating system environment.

5.Functions can not be invoked from SQL Statements. Execute. SELECT
operating system can be invoked from SQL Statements. Execute. SELECT

6.Functions can run an executable file from SQL SELECT or an action query.
operating system use Execute or Exec to run
 
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Features	Procedures	Functions
Parameters	Supports in, out, in & out	Only supports in
Temp Object	Accessible – You can use the temp tables inside the procedure	Not supported
Create as Temp	Accepted – Create Proc #MyProc..	Not supported
Select Result	Supported	Not supported
Return	Return integer value	Returns any type of value
On DML Quires	Not allowed	You can embed the function on query
Calling SPs	Allowed	Not Allowed
Calling Another Functions	Allowed	Allowed
Insert/Update/Delete	Allowed	Not Allowed Or Only allowed against the table variables
Recursive Operation	Allowed	Allowed
Versioning (grouped)	Allowed	Not Allowed
Schema Binding	Not Allowed	Allowed
Creating Objects	Allowed	Not Allowed
EXEC	Allowed	Not Allowed
SP_EXECUTESQL Dynamic SQL	Allowed	Not Allowed
GETDATE() or other non-deterministic functions	Allowed	Not Allowed
SET OPTION	Not Allowed	Allowed
Setting Permission Grant/Deny	Yes	No for scalar functions. Yes for Table Values/Inline Functions

Thanks
Alok Kumar Sharma