Question 22190 in Mysql Question posted in
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How do I return a value from another column by matching an input from a function? – Mysql

Table

CREATE DEFINER=`root`@`localhost` FUNCTION `GetGPA`(sName VARCHAR(45)) RETURNS float
    DETERMINISTIC
BEGIN
DECLARE grade FLOAT;
DECLARE sName VARCHAR(45);

SELECT GPA INTO grade
FROM student
WHERE studentName = sName;

RETURN grade;
END

I did the function and it returned null:
Stored Function

I tried returning a student’s GPA using a function inputting a student’s name.

Tags:

2

Answers


  1. 0

    when you used Into key word,that means you create temp table.
    so far you should be use a variable that its type equal with GPA column and set value on in,finally return it:

    CREATE DEFINER=`root`@`localhost` FUNCTION `GetGPA`(sName VARCHAR(45)) RETURNS float
    DETERMINISTIC
BEGIN
DECLARE @grade FLOAT;
DECLARE sName VARCHAR(45);

SELECT @grade=GPA  
FROM student
WHERE studentName = sName;

RETURN @grade;
END
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  2. 0

    Use:

    CREATE FUNCTION GetGPA (sname varchar(45)) 
  RETURNS float DETERMINISTIC
BEGIN
 DECLARE grade FLOAT;
   SELECT GPA INTO grade
   FROM student
   WHERE StudentName = sName;
  RETURN grade;
END

    https://dbfiddle.uk/AF9iO_l8

    Reference

    The only problem in your function is DECLARE sName VARCHAR(45); remove that part and your function is ok

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