SQL Query fields as columns

Question

I dont really know how to put this but please kindly check the details below.

Student

|Student_ID|Student_Name|
|1         |Ryan             


        

Answer 1

While @John's answer will work if you have a known number of subjects, if you have an unknown number of subjects then you can use prepared statements to generate this dynamically. Here is a good article:

Dynamic pivot tables (transform rows to columns)

Your code would look like this:

SET @sql = NULL;
SELECT
  GROUP_CONCAT(DISTINCT
    CONCAT(
      'MAX(case when Subject = ''',
      Subject,
      ''' then Grade end) AS ',
      Subject
    )
  ) INTO @sql
FROM grade;

SET @sql = CONCAT('SELECT s.Student_name, ', @sql, ' 
                   FROM student s
                   LEFT JOIN grade AS g 
                    ON s.student_id = g.student_id
                   GROUP BY s.Student_name');

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

See SQL Fiddle With Demo

Answer 2

Try,

SELECT  a.Student_name,
        MAX(CASE WHEN subject = 'MATH' THEN grade ELSE NULL END) MathGrade,
        MAX(CASE WHEN subject = 'ENGLISH' THEN grade ELSE NULL END) EnglishGrade,
        MAX(CASE WHEN subject = 'History' THEN grade ELSE NULL END) HistoryGrade
FROM    Student a
        LEFT JOIN Grade b
            ON a.Student_ID = b.Student_ID
GROUP BY a.Student_name

SQLFiddle Demo