DECLARE @groupCount bigint = 1;
DECLARE @currentGroupId int;

WHILE @groupCount <= (
    SELECT COUNT(*) FROM dbo.Группы
);

BEGIN
    DECLARE @groupId int;
    DECLARE @subjectId int;

    SET @currentGroupId = (
        SELECT Номер
        FROM dbo.Группы
        WHERE Номер = @groupCount
    );

    DECLARE @subjectCursor CURSOR FOR
        SELECT ID, ROW_NUMBER() OVER (ORDER BY ID) AS subjectRowNumber
        FROM dbo.Предметы;

    OPEN @subjectCursor;
    FETCH NEXT FROM @subjectCursor INTO @subjectId, @subjectRowNumber;

    WHILE @subjectRowNumber <= (
        SELECT MAX(ROW_NUMBER()) OVER (ORDER BY ID) AS maxRowNumber
        FROM dbo.Предметы
    );

        BEGIN
            INSERT INTO dbo.Изучение (
                Группа_Номер,
                ID_Предмета,
                Часы,
                Вид_аттестации
            )
            VALUES (
                @currentGroupId,
                @subjectId,
                10,
                'Экзамен'
            );

            FETCH NEXT FROM @subjectCursor INTO @subjectId, @subjectRowNumber;
        END;

    CLOSE @subjectCursor;

    SET @groupCount = @groupCount + 1;
END;