What is SQL function?
SQL functions are methods which accept parameters and perform the action, such as a complex calculation and return the result of that action as a value.the return value can either be a single scalar value ,result set. We can’t use a function to Insert, Update, Delete records in the database table(s).
Available types of functions in SQL.
- Scalar Functions
- Table-Valued Functions
- System Function
What is the stored procedure?
Stored Procedures are pre-compiled objects which are compiled for the first time and its compiled format is saved which executes whenever it is called.
Difference between SQL function and Stored procedure?
- A function must return a value but in Stored Procedure, it is optional( Procedure can return zero or n values).
- Functions can have only input parameters for it whereas Procedures can have input/output parameters.
- Functions can be called from Procedure whereas Procedures cannot be called from Function.
- The procedure allows SELECT as well as Insert, Update, Delete statement where Function allows only SELECT statement.
- Procedures cannot be utilized in a SELECT statement whereas Function can be embedded in a SELECT statement.
- Stored Procedures cannot be used in the SQL statements anywhere in the WHERE/HAVING/SELECT section whereas Function can be.
- Inline Function can be thought of as views that take parameters and can be used in JOINs and other Rowset operations.
- We can handle Exception by try-catch block in a Procedure but not in functions.
- We can perform Transaction Management in Procedure whereas we can’t go in Function.
Can we call the Stored procedure inside SQL function?
No, You cannot execute a stored procedure inside a function, because a function is not allowed to modify database state, and stored procedures are allowed to modify database state.
Can we call a function inside the Stored procedure?
Yes, We can call functions inside the stored procedures.
Is Row_Number generate duplicate Id?
No, ROW_NUMBER Returns a unique number for each row starting with 1. For rows that have duplicate values, numbers are arbitrarily assigned.
what is Scope identity in SQL?
Scope_Identity returns the last identity value generated in the current scope (i.e. stored procedure, trigger, function, etc).
What is CTE in SQL?
A common table expression (CTE) can be thought of as a temporary result set that is defined within the execution scope of a single SELECT, INSERT, UPDATE, DELETE, or CREATE VIEW statement. A CTE is similar to a derived table in that it is not stored as an object and lasts only for the duration of the query. Unlike a derived table, a CTE can be self-referencing and can be referenced multiple times in the same query.