Get all records in first tbl and matching in second tbl (indicating ones that existed)

Question

Looking to get ALL UserName from UsersDataTbl and matching UserName from EnrollmentsTbl if it exist. but I want to identify w

Answer 1

You can us the is not null to test if a field's value is null or not and return a true or false. If the username does not exist in EnrollmentsTbl then the left join will return null in its place.

I moved the e.ClassName LIKE 'Word% criterion from the where clause to the join condition, since it changed the left join into an inner join defeating the whole purpose of the query.

SELECT u.UserName
     , (e.UserName IS NOT NULL) as user_exists_in_EnrollmentsTbl 
  FROM UsersDataTbl u
  LEFT 
  JOIN EnrollmentsTbl e
    ON u.UserName = e.UserName 
        AND e.ClassName LIKE 'Word%'
 WHERE u.UserName LIKE 'bar%'