简单的mysql函数语法错误1064

I cant figure outt the error in this function that i wrote. I suspect that it must be something with type casting. i tried to comment part by part to see where the error may be and it was somewhere after the first IF and before return. I would really appreciate if someone could help me figure it out. the error is 1064 and it says that syntax is missing near ' ' line 33.I cant figure outt the error in this function t