使用join从2个以上的表中获取记录

Question

Here is my table structure:

Table 1

  id | question | posted_id

Table 2

  id | username | email  

Table 3

 id | reader_id | quote_id

I want to fetch those question which are not read by particular user.I also want email from table2 in result set. So I created Below query that join my two table1 and table2. My query:

SELECT table1.id,table1.question,table1.posted_id,table2.email 
FROM table1,table2 
WHERE table1.post_id = table.id;   

How to fix a left join on table 3 for filter the records Because I need questions which are not read by particular user.

Answer 1

I am not sure which user field you are trying to match against, i have taken email, Also this will only give matching records, Try

SELECT T1.*,T2.email
FROM Table1 AS T1
INNER JOIN Table2 AS T2 ON T2.quote_id = T1.id
INNER JOIN Table3 AS T3 ON T3.reader_id = T2.id
WHERE T2.email='some_mail_id'