Whats the difference between stored procedure & trigger?

1. We can execute a stored procedure whenever we want with the help of the exec command, but a trigger can only be executed whenever an event (insert, delete, and update) is fired on the table on which the trigger is defined.
2. We can call a stored procedure from inside another stored procedure but we can't directly call another trigger within a trigger. We can only achieve nesting of triggers in which the action (insert, delete, and update) defined within a trigger can initiate execution of another trigger defined on the same table or a different table.
3. Stored procedures can be scheduled through a job to execute on a predefined time, but we can't schedule a trigger.
4. Stored procedure can take input parameters, but we can't pass parameters as input to a trigger.
5. Stored procedures can return values but a trigger cannot return a value.
6. We can use Print commands inside a stored procedure for debugging purposes but we can't use print commands inside a trigger.
7. We can use transaction statements like begin transaction, commit transaction, and rollback inside a stored procedure but we can't use transaction statements inside a trigger.
8. We can call a stored procedure from the front end (.asp files, .aspx files, .ascx files, etc.) but we can't call a trigger from these files.
9. Stored procedures are used for performing tasks. Stored procedures are normally used for performing user specified tasks. They can have parameters and return multiple results sets.
10. The Triggers for auditing work: Triggers normally are used for auditing work. They can be used to trace the activities of table events.

triggers are queries executed when some events happend.

stored procedures are queries executed by user calls via EXEC command.