Sql Query (Database MS Access or Sql server)

I have four tables, B1, B2 and C1, C2.
B1 is linked with B2 and C1 is linked with C2 with a numeric id.

I need to write a query that pulls data from B1, B2 and C1, C2 tables.

Please advice.

insufficient information

if B1-B2 are not related to C1-C2, you need to explain how you want a single query to return data from them, and furthermore, what data?

i appreciate you may want to keep application concept or ideas confidential, but what you posted is unfortunately oversimplified

“make things as simple as possible, but no simpler” - albert einstein