mySQL查询函数的语法错误，将小数等级转换为字母等级

Question

I'm having troubles with a syntax error when trying to create a function in MySQL to convert a decimal grade into a letter grade.

What could be the issue?

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your mySQL server version for the right syntax to use near 'conv(gpa DOUBLE) RETURNS CHAR BEGIN
DECLARE grade CHAR;
SELECT CASE WHEN gp' at line 1

Here is my code:

delimiter $

CREATE FUNCTION conv(gpa DOUBLE) 
RETURNS CHAR
BEGIN 

DECLARE grade CHAR; 

SELECT CASE WHEN gpa BETWEEN 3.5 AND 4.0 THEN 'A' 
WHEN gpa BETWEEN 3.0 AND 3.4 THEN 'B' 
WHEN gpa BETWEEN 2.5 AND 2.9 THEN 'C' 
WHEN gpa BETWEEN 2.0 AND 2.4 THEN 'D' 
ELSE 'F' 
END INTO grade 

RETURN grade;

END $

Answer 1

You're missing a semi-colon near the end:

SELECT CASE WHEN gpa BETWEEN 3.5 AND 4.0 THEN 'A' 
WHEN gpa BETWEEN 3.0 AND 3.4 THEN 'B' 
WHEN gpa BETWEEN 2.5 AND 2.9 THEN 'C' 
WHEN gpa BETWEEN 2.0 AND 2.4 THEN 'D' 
ELSE 'F' 
END INTO grade;

Also, you probably shouldn't use the name conv as this is already means something else .