In SQL Server, the CHOOSE function returns the item at the provided index from a list of values. CHOOSE is an index into an array, with the array being made up of the arguments that come after the index argument. The index argument determines which of the values will be returned.
The value is implicitly transformed to an integer if the specified index value has a numeric data type other than int. If the index value is greater than the array’s boundaries, CHOOSE returns null.
SELECT CHOOSE ( 1, ‘Scott’, ‘Wills’, ‘Miller’, ‘Mia’ ) AS Result;
Let’s continue with a useful dataset to better understand the function’s behavior.
–Setting up the data-set.
CREATE TABLE tbStudentDetails(
INSERT INTO tbStudentDetails VALUES
SELECT * FROM tbStudentDetails
The result is-
StudentID StudentName GradeID
1001 Zafar Iqbal 2
1002 Tahir Iqbal 1
1003 Danial Hussain 3
Now, lets use “CHOOSE” function to convert the “GradeID” into actual grades.
StudentID StudentName GradeID Grade
1001 Zafar Iqbal 2 A
1002 Tahir Iqbal 1 A+
1003 Danial Hussain 3 B
It considers the lowest number first, and assigns the first input value.
Hope you find this article helpful.