相关疑难解决方法(0)

我有一个SQLite数据库.我试图在表中插入值(users_id,lessoninfo_id),前提bookmarks是它们之前不存在.

INSERT INTO bookmarks(users_id,lessoninfo_id) 
VALUES(
    (SELECT _id FROM Users WHERE User='"+$('#user_lesson').html()+"'),
        (SELECT _id FROM lessoninfo 
        WHERE Lesson="+lesson_no+" AND cast(starttime AS int)="+Math.floor(result_set.rows.item(markerCount-1).starttime)+") 
        WHERE NOT EXISTS (
            SELECT users_id,lessoninfo_id from bookmarks 
            WHERE users_id=(SELECT _id FROM Users 
            WHERE User='"+$('#user_lesson').html()+"') AND lessoninfo_id=(
                SELECT _id FROM lessoninfo
                WHERE Lesson="+lesson_no+")))

这给出了一个错误说:

db error附近的语法.