How to join different table some column? - sql

Question

Student Table 1
ID Name Surname School Number Class Number ClassBranch
-----------------------------------------------------------------------------
113 Jane Smith 19 4 A
121 John Konl 42 5 B
331 Albert Smith 61 4 A
742 Jack Ronal 52 5 B
759 Jan Ronal 84 6 C
Student Table 2
ID Name Surname School Number Class Number Class Branch
-----------------------------------------------------------------------------
113 Jane Smith 11 4 D
151 John Konl 18 4 D
804 Albert Smith 26 5 F
605 Jack Ronal 32 5 F
785 Jan Ronal 87 8 L
Created Student Table
ID Name Surname School Number Class Number Class Branch
--------------------------------------------------------------------
113 Jane Smith NULL NULL NULL
151 John Konl NULL NULL NULL
804 Albert Smith NULL NULL NULL
605 Jack Ronal NULL NULL NULL
NULL NULL NULL 11 4 D
NULL NULL NULL 18 4 D
NULL NULL NULL 26 5 F
NULL NULL NULL 32 5 F
I want this table
ID Name Surname School Number Class Number Class Branch
113 Jane Smith 11 4 D
151 John Konl 18 4 D
804 Albert Smith 26 5 F
605 Jack Ronal 32 5 F
I want to Student Table 1 ---> ID,Name,Surname and Student Table 2 --> School Number,Class Number and ClassBranch joın.But joın is not successful.Class Branch A and B removed and D,F is adding.
First table ID,Name,Surname (3 columns) and Second table School Number,Class Number,Class Branch join.
Where conditions:
Removed column --> 4 - A AND 5 - B
Adding column --> 4- D AND 5- F
How can I write query?

Answer 1

Now that you've completely changed the original tables, this should be a simple JOIN.
SELECT t2.id, t1.name, t1.surname, t2.SchoolNumber, t2.ClassNumber, t2.ClassBranch
FROM Student1 AS t1
JOIN Student2 AS t2 ON t1.name = t2.name AND t1.surname = t2.surname
DEMO

Answer 2

To get those results?
1) The complicated way. By joining them.
SELECT
s2.ID,
s1.Name, s1.Surname,
s2."School Number", s2."Class Number", s2.ClassBranch
FROM Student1 AS s1
JOIN Student2 AS s2 ON (s2.Name = s1.Name AND s2.Surname = s1.Surname)
WHERE s1."Class Number" IN (4, 5);
2) The simple way, select only from the 2nd table
SELECT *
FROM Student2
WHERE "Class Number" IN (4, 5);
Test on SQL Fiddle here