Question

I have user related info split into multiple tables . I am trying to write a join to retrieve data for a single user , a lot of the info is optional , so the entry for many columns may be null , which is okay . I have written the following query , it is working except that it returns all users when I want the user with id ’69’

SELECT cur_doctor_names.First_Name, cur_doctor_Names.Last_Name, w.Website
FROM cur_doctor_names
LEFT JOIN (

SELECT *
FROM cur_website
WHERE Userid =69
) AS w ON cur_doctor_names.UserId = w.Userid

I want the following result :

First_Name | Last Name | Website 
ABC          XYZ         Null    

where ABC is the name for user with id 69 .

Answer 1

You are only filtering the websites because you are using a left join. You should apply your filter to the doctors table

SELECT 
    cur_doctor_names.First_Name, 
    cur_doctor_Names.Last_Name, 
    w.Website 
FROM 
    cur_doctor_names 
        LEFT JOIN cur_website AS w 
        ON cur_doctor_names.UserId = w.Userid 
WHERE     
    cur_doctor_names.UserId = 69