Hello,
If I understand you correctly, you are trying to store multiple grades in one text/varchar column.
To do this, the first grade would be put into the database using an INSERT statement with each consecutive grade getting inserted by an UPDATE statement because we are updating an existing record. Try doing something such as:
UPDATE tbl_studentgrade SET
grade = grade || ' 78'
WHERE student = 'Some Student ID'
Note that the new grade is padded with a leading space.
A more sophisticated approach might be to separate the student, grade, and assignment into separate tables.
Good luck,
Dan
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