How do i select rows of table if value of a column is 0 else do left join if value is not 0 in sql?

Question

I want to get values of few columns of 'table1' if value of 'test' column of table1 is 0 else do left join with 'table2' and select few columns of 'table2' in sql?

Both table have different number of columns with different names.

Answer 1

SELECT t1.join_column,
       t1.anycase_column,
       CASE WHEN t2.join_column IS NULL
            THEN t1.case_column
            ELSE t2.case_column 
            END case_column
FROM table1 t1
LEFT JOIN table2 t2 ON t1.join_column = t2.join_column
                   AND t1.check_column != 0