Question

TB1, TB2, TB3 are in one database on the server and TB4 is on another database.

The column information needed for the join are as follows:

• TB1 – column a1, b2.
• TB2 – column a2, b2, c3.
• TB3 – column a3.
• TB4 – column a4.

TB1, TB2, TB3 are related by ID
TB1’s ID is the primary key and the foreign keys in TB2, TB3 and TB4

I am using SQL Server Management Studio

Code:

select ID
from TB1, TB2, TB3
where TB1.ID = TB2.TB1.ID

Answer 1

You can link them like this (don’t forget to put the relation that you missed to say):

SELECT t1.a1, t1.b2, t2.a2, t2.b2, t2.c3, t3.a3, t4.a4
FROM db1..TB1 t1
INNER JOIN db1..TB2 t2 ON t1.ID = t2.ID
INNER JOIN db1..TB3 t3 ON t1.ID = t3.ID
INNER JOIN db2..TB4 t4 ON --put relation here

Also replace db1 and db2 by the database names on which each table is present.

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One final note, your code it’s giving redundant information because you didn’t make all the restrictions. So, a cartesian product is produced.