Question

I have a query where I want to join to another table if the field has either one value or another. How would I go about doing that? Should I use an or statement? (Is that even possible?) Or will an IN statement suffice?

SELECT table1.field1,table2.field2 FROM table1
INNER JOIN table2 ON table1.field1 = table2.field2 OR table2.field2 = 0

Basically the field in table 2 can either be a match from table 1 or the number 0, I want to make the match on either or. So if there is no match from table1 field and table2 field but there is a 0 in table2 field then I want to join the table. Hope that makes sense. Or would this work/be better?

SELECT table1.field1,table2.field2 FROM table1
INNER JOIN table2 ON table1.field1 IN(table2.field2,0)

Answer 1

I’d think about it slightly differently and start with table2.

SELECT table1.field1, table2.field2
    FROM table2
        LEFT JOIN table1
            ON table2.field2 = table1.field1
    WHERE table2.field2 = 0
        OR table1.field1 IS NOT NULL