Select-when using MySql Navicat to create a stored procedure, error 1458 is always reported.

The following is the code of the wearing procedure. Please help me. We are so anxious that we will use it tomorrow. & Quot; createproceduresearchStudentGrade (inidchar) beginifidisnullselectstudent. studentID, student. studentName, student. classNumber, grade. examID, course. courseName, grade. grade, course. courseIDfromstudent, grad... selectmysql stored procedure

The following is the code of the wearing procedure. Please help me. We are so anxious that we will use it tomorrow.

Create procedure searchStudentGrade (in id char) begin if id is null select student. studentID, student. studentName, student. classNumber, grade. examID, course. courseName, grade. grade, course. courseID from student, grade, course where student. studentID = grade. studentID and grade. courseID = course. courseID; else select student. studentID, student. studentName, student. classNumber, grade. examID, course. courseName, grade. grade, course. courseID from student, grade, course where student. studentID = grade. studentID and grade. courseID = course. courseID and grade. studentID = id; end if; end;