MySQL Left Joins: Select everything from one table, but only matching value in second table with criteria

Question

I have two tables. I want to select everything from one table and the matching row from the second table - that matches a criteria.

So tblConfig_Group contains a list of groups.

|ID | groupCode | 
|1  | A         |
|2  | B         |
|3  | C         |
|4  | D         |

And tblConfig_CustomerGroup contains a list of groups and customers in that those groups.

|ID | groupCode | customerID |
|1  | A         | 74         |
|2  | B         | 74         |
|3  | A         | 235        |
|4  | C         | 74         |

It should only display rows from the second table where there is a match AND criteria ( customerID = 74)

EXPECTED RESULTS:

|ID | groupCode | customerID |
|1  | A         | 74         |
|2  | B         | 74         |
|3  | C         | 74         |
|4  | D         |            |

I've tried a number of queries but it doesn't seem to work for me...

SQL Query 1:

SELECT g.groupCode,  cg.customerID FROM tblConfig_Group g 
LEFT JOIN tblConfig_CustomerGroup cg ON g.groupCode = cg.groupCode  
WHERE cg.customerID = '74'

ACTUAL RESULTS: rows 1, 2 & 3.

| groupCode | customerID |
| A         | 74         |
| B         | 74         |
| A         | 74         |

SQL Query 2:

SELECT g.groupCode,  cg.customerID FROM tblConfig_Group g 
left outer join tblConfig_CustomerGroup cg on g.groupCode = cg.groupCode   
WHERE cg.customerID = '74' 
UNION  
SELECT g.groupCode, cg.customerID 
FROM tblConfig_Group g 
right outer join tblConfig_CustomerGroup cg on g.groupCode = cg.groupCode

ACTUAL RESULTS: rows 1, 2 & 3 + customer 235

| groupCode | customerID |
| A         | 74         |
| B         | 74         |
| A         | 74         |
| A         | 235        |

Answer 1

SELECT 
  g.id,
  g.groupCode, 
  cg.customerID 
FROM tblConfig_Group g 
LEFT JOIN tblConfig_CustomerGroup cg 
ON g.groupCode = cg.groupCode 
  AND cg.customerID = '74';

Answer 2

Your first query is essentially correct but just missing a tiny bit to include the nulls

SELECT g.groupCode, cg.customerID FROM tblConfig_Group g
LEFT JOIN tblConfig_CustomerGroup cg 
ON g.groupCode = cg.groupCode WHERE cg.customerID = '74'
OR cg.customerID IS NULL;

Another solution is

SELECT g.groupCode, cg.customerID FROM tblConfig_Group g
LEFT JOIN 
   (SELECT * FROM tblConfig_CustomerGroup 
    WHERE customerID = '74') AS cg 
ON g.groupCode = cg.groupCode