1 | initial version |
If the desired column for joining is empty or null, the following steps can be taken:
SELECT * FROM table1 JOIN table2 ON table1.column1 = table2.column2 or table1.column1 IS NULL
SELECT * FROM table1 JOIN table2 ON COALESCE(table1.column1, 'defaultValue') = table2.column2
SELECT * FROM table1 LEFT OUTER JOIN table2 ON table1.column1 = table2.column2