Google Sheets query column=column

Question

I am not familiar with google sheets, but I have been sent an assignment and I don't want to take the time to convert the whole thing over to an actual database. Is a way to take one column of values (A) and another (B) and check if there is any value in A that is equal to any value in B via queries. I tried

=query(*table*, "SELECT *name of row* WHEN A=B", 1)  

but that just seems to check each row.

For you visual types, I have a database

  | A | B |
--+---+---+ 
1 | 1 | 0 |
--+---+---+ 
2 | 1 | 2 |
--+---+---+
3 | 1 | 1 |
--+---+---+
4 | 2 | 3 |

I want to select rows 2 and 3.
I didn't see a duplicate. Doesn't help how Google doesn't really document this stuff very well.

Answer 1

this is how you use query:

=QUERY(A1:B; "select B where A = '1'"; 0)

• A1:B - the range you want to import
• select B - select all columns of given range
• where A = '1' - where in column A are cells with content 1
• 1 - stands for 1 heading row (0 for no rows, 2 for two rows, etc.)

---

but maybe you seek this:

=ARRAYFORMULA(IF(A1:A=B1:B; "match"; ))

and query version would be:

=QUERY(A1:B; "select A where A=B"; 0)