两个表上的 SQL 连接，这两个表都为 WHERE 子句提供参数

Question

Does the following SQL Query work?

SELECT domains.domainURL, passwords.* FROM domains LEFT JOIN passwords ON domains.id = passwords.domainId WHERE domains.domainURL = {1} AND passwords.userId = {2};

The SQL Query shall receive the password that the user has saved for a specific domain(PW Manager). Therefore I have the user Id and the domainURL. I need to receive the domain Id from another table with the domainURL. Then I need to receive the password from the passwords table with the user Id and the domainId as argument.

Answer 1

Will this query "work"?

SELECT d.domainURL, p.*
FROM domains d LEFT JOIN
     passwords p
     ON d.id = p.domainId
WHERE d.domainURL = {1} AND p.userId = {2};

Well, it should not result in an error -- assuming that the tables and columns are correct. Does it do what you want? Well, if you want an INNER JOIN , it does what you want.

I suspect that you might intend:

SELECT d.domainURL, p.*
FROM domains d LEFT JOIN
     passwords p
     ON d.id = p.domainId AND p.userId = {2} 
WHERE d.domainURL = {1};

This will return the row from passwords if it exists . It will return all rows from domains that match the WHERE clause.