SQL Interview Questions with Answers on Defined Functions

What is User Defined Functions?
User-Defined Functions allow to define its own T-SQL functions that can accept 0 or more parameters
and return a single scalar data value or a table data type.

What kind of User-Defined Functions can be created?
There are three types of User-Defined functions in SQL Server 2000 and they are Scalar, Inline Table-
Valued and Multi-statement Table-valued.

Scalar User-Defined Function
A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp
data types are not supported. These are the type of user-defined functions that most developers are
used to in other programming languages. You pass in 0 to many parameters and you get a return
value.

How to find out Max Salary from each department

You can find maximum salary for each department by grouping all records by DeptId and then using MAX() function to calculate maximum salary in each group or each department. SQL Query: SELECT DeptID, MAX(Salary) FROM Employee GROUP BY DeptID. This questions become more interesting if Interviewer will ask you to print department name instead of department id, in that case you need to join Employee table with Department using foreign key DeptID, make sure you do LEFT or RIGHT OUTER JOIN to include departments without any employee as well. Here is the query

List the emps who joined before 1981.

Answer: select * from emp where hiredate < (’01-jan-81’);

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