从table1中进行选择，条件是table1中的条件特定元素不存在于table2中

Question

表words包含列： word_id word

我的查询显示为：

SELECT word FROM words WHERE condition1 AND condition2 ORDER BY RAND() LIMIT 5000

solved表包含以下列： user_id word_id

我想获取5000个随机行，条件是在为user = username solved的表中找不到任何随机行

到目前为止，我已经尝试过：

SELECT word FROM words w 
WHERE not exists 
(select 1 from solved s where s.word_id = w.word_id 
AND s.user_id = 'username') 
AND condition1 AND condition2 ORDER BY RAND() LIMIT 5000

Answer 1

使用LEFT JOIN进行thar：

SELECT word 
FROM words w 
left join solved s on s.word_id = w.word_id AND s.user_id = 'username'
WHERE w.word_id is null
AND condition1 AND condition2 
ORDER BY RAND() LIMIT 5000