I have two tables.
The first one is: Project Table
ID | SN | pTypeID
----|----------|-------
1 | project1 | 1
2 | project2 | 3
3 | project3 | NULL
4 | project4 | NULL
ID | Name
----|---------
1 | pType1
2 | pType2
3 | ptype3
ID | SN | Name
----|----------|--------
1 | project1 | pType1
2 | project2 | pType3
3 | project3 | NULL
4 | project4 | NULL
SELECT Project.ID, Project.SN, pType.Name
FROM Project
INNER JOIN Type ON Project.pTypeID = pType.ID
I believe you want to left join on pType
select p.id, p.sn, t.name
from Project as p
left join pType as t on p.pTypeID = t.id;