SQL: select from table where it doesnt exist in other for a user -


i have 2 tables, test , studenttest these structures:

test:

testid     subject     totalpoints     schoolsubject 1          programming 100             informatics 2          webdesign   80              informatics ...

studenttest:

studenttestid     userid     testid     timestudied     points     date 1                 1          1          60              60         2015-05-20 2                 2          1          100             80         2015-05-20 2                 2          2          95             75         2015-05-20 ...

now want make page user can fill in marks (in studenttest), want show tests user doesn't have marks for. example if user 1 logged in should see test 2 because user 1 has no marks test. user 2 shouldn't see because has marks existing tests.

i don't know sql should like.

can me please?

you can use exists operator:

select subject, schoolsubject   test t  not exists (select *                      studenttest st                     t.testid = st.testid                    -- , possibly limit single studentid                   )

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