MySQL选择与另一个表记录对应的行

Question

Ok, so I have a table that contains optionID, optionName. Its called user_options. I have a second table that contains userID, optionID. Its called user_selected_options.

Options in user_options are stored for a user in user_selected_options, which is fine. Now, when editing a user, I just want to show the options from user_options which are not selected for that user in user_selected_options as select boxes. How can I do this?

I hope this question make sense. Please let me know if it is unclear and I will explain further.

Thanks for any tips.

Answer 1

Here is one method using not exists :

select uo.*
from user_options uo
where not exists (select 1
                  from user_selected_options uso
                  where uso.optionId = uo.option_id and uso.userId = $userId
                 );

For best performance, create an index on user_selected_options(option_id, userId) .

Answer 2

you can use from not in command of mysql for example:

select * from user_options where optionID NOT IN(select optionID from user_selected_options where userID=10)

see more examples about NOT IN http://www.w3resource.com/mysql/comparision-functions-and-operators/not-in.php