i am working with a Postgresql database

having two tables: professionals[professional_id,user_id,account_id] users[user_id email] accounts[account_id email]

professionals

 [professional_id,user_id,account_id]
     
    1,          2000,       null
    2,          3000,        120
    3,          4000,        155

users

   [user_id,   email]
    2000,   [email protected]
    3000,   [email protected]
    4000,   [email protected]

accounts

   [account_id ,    email]
   120,          [email protected]
   155,         [email protected]

Here i have to get the email with doing a join between accounts and professionals.

If account_id is not null we get the email

If the account_id is null we do the join between the users and professionals (we are sure that user_id is always not null)

Here is what i did :

select email from professionals  
IF (u.id=m.user2ID)
left JOIN accounts ON accounts.account_id = professionals.account_id
ELSE
LEFT JOIN users  ON users.user_id = professionals.user_id;

Thanks indeed for any help

i am working with a Postgresql database

having two tables: professionals[professional_id,user_id,account_id]

users[user_id email]

accounts[account_id email]

professionals

 [professional_id,user_id,account_id]
     
    1,          2000,       null
    2,          3000,        120
    3,          4000,        155

users

   [user_id,   email]
    2000,   [email protected]
    3000,   [email protected]
    4000,   [email protected]

accounts

   [account_id ,    email]
   120,          [email protected]
   155,         [email protected]

Here i have to get the email with doing a join between accounts and professionals.

If account_id is not null we get the email

If the account_id is null we do the join between the users and professionals (we are sure that user_id is always not null)

Here is what i did :

select email from professionals  
IF (u.id=m.user2ID)
left JOIN accounts ON accounts.account_id = professionals.account_id
ELSE
LEFT JOIN users  ON users.user_id = professionals.user_id;

Thanks indeed for any help