Combine 2 tables

  • Hi,

    academic

    ID    | year  | level   | m_l

    ----------------------------------------------

    147   | 2006  | dip     | 20

    course

    ID    | year  | level   | course_desc   | m_l

    ----------------------------------------------

    147   | 2006  | dip     | k             | 7

    147   | 2006  | dip     | b             | 11

    Hint

    ----

    (1) see course table, select sum(m_l) from course where ID=147 and year=2006 and level='dip' = 18

    (2) after query from (1), if user select ID=147, year=2006, level=dip, then m_l receiving 2 or less only (0,1,2).

    My problem is 'How to query from academic and course', then result shown as follow:-

    ID    | year  | level  | value_left_in_course

    ----------------------------------------------

    147   | 2006  | dip    | 2

    regards.

  • Hi there,

    somthing along the lines of the folowing should work:

    SELECT a.ID, a.Year, a.Level, a.m_l - c.m_l [value_left_in_course]

    FROM

    academic a

    LEFT JOIN

    (SELECT SUM(m_l) [m_l] FROM course GROUP BY ID) b

    ON a.ID = b.ID

    HTH,

    - James

    --
    James Moore
    Red Gate Software Ltd

  • This looks like homework. Please do not ask us to solve your homework questions. You should be digging in and writing your own SQL.

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