结合使用MySQL选择查询和子查询

Question

I am trying to select rows of data from a table where user_id does not equal the uder_id of the user logged in and where the user_id is not in the sub query. For some reason I can't get it to work. What could I doing wrong?

My Code:

SELECT * 
FROM table_name 
WHERE user_id != '".$_SESSION['id']."' 
    AND user_id NOT IN(
      SELECT * FROM another_table_name where user1= '".$user_id."' AND status= 1)
ORDER BY RAND()
LIMIT 5

Answer 1

You have to select only the user_id from another_table_name . Without seeing your table structure i am not able to help you further.

Answer 2

Your logic is correct. What we don't know are the parameterized values in the query. My guess is those are not equal to the values you are expecting.

Answer 3

In your sub query you just want to select user_ids , you have your sub query using a "select *"

SELECT * FROM table_name WHERE user_id != '".{$_SESSION['id']}."' AND user_id NOT IN(SELECT    
user_id FROM another_table_name where user1= '".$user_id."' AND status= 1) ORDER BY RAND()     LIMIT   5

Answer 4

You'll need to only select the user_id s from the sub query. Maybe something like:

SELECT * 
  FROM table_name 
  WHERE user_id != '".{$_SESSION['id']}."' 
    AND user_id NOT IN(SELECT user_id 
      FROM another_table_name 
      WHERE user1= '".$user_id."' 
      AND status= 1) 
  ORDER BY RAND() 
  LIMIT 5