选择其他表中不存在值的行

Question

I've got two tables. One for main accounts and one for banned accounts and I wanna select all the members in the main accounts and only those who is not banned.

SELECT Username, $field AS Output
FROM `Player_Accounts`, `Ban_List`
WHERE Ban_List.Banned_Name != Username
ORDER BY $field DESC LIMIT 0, 25;

The query take over 1,30min to execute and display the results

Answer 1

IMHO your query is not right. The number of rows are very high (have you 1.3 million of users???)

Try this:

SELECT p.username
FROM Player_Accounts p
WHERE NOT EXISTS(
    SELECT 'BANNED'
    FROM Ban_List b
    WHERE b.banned_name = p.username
)

Alternative:

SELECT p.username
FROM Player_Accounts p
LEFT OUTER JOIN Ban_List b
ON p.username = b.banned_name
WHERE b.banned_name IS NULL