mysql查询-没有更多条目具有相同的qID和相同的用户ID

Question

The following description is a simple example with questions and answers. But the logic of my site is similar.

Lets say tables are:

USERS table: USER_ID, etc
QUESTIONS table: QUESTION_ID, TEXT, CATEGORY, CORRECT_RESPONSE, AVAILABLE
RESPONSES table: QUESTION_ID, USER_ID, RESPONSE_VALUE
PROFILE table: USER_ID, CATEGORY_Questions, YEAR, NUMBER_OF_ANSWERED, Number_OF_CORRECT, POINTS

The questions will be available to be answered by users for few hours. Every question has the same 3 choices for answers YES/NO/DEPENDS.

So I want users to go click on one of them for example and store an entry on RESPONSES table (ok this query is easy) and then not be able to answer the same question again. Users will be able to edit the question for some time and after this period I want the question to be shown as answered, until the end of the day that I will mark the question as AVAILABLE=NO and it will removed from the unanswered questions... What is the most efficient way to do this?

Answer 1

有很多的方式来实现这个要看具体情况，其中之一是创建一个布尔bit叫回答柱和另一列AnswerDate datetime or timestamp ，然后当用户回答一个问题添加答案的时间，然后使用PHP或JavaScript在处理更新所需时间过后，表中已answered的标志的数量。