When joining in SQL Server, what steps can be taken if the desired column for joining is empty or null?

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If the desired column for joining is empty or null, the following steps can be taken:

1. Use the IS NULL operator to check for null values in the joining column. For example:

SELECT * FROM table1 JOIN table2 ON table1.column1 = table2.column2 or table1.column1 IS NULL

1. Use the COALESCE function to replace null values with a default value. For example:

SELECT * FROM table1 JOIN table2 ON COALESCE(table1.column1, 'defaultValue') = table2.column2

1. Use a LEFT OUTER JOIN if you want to include all the rows from the left table even if there is no match on the joining column. For example:

SELECT * FROM table1 LEFT OUTER JOIN table2 ON table1.column1 = table2.column2

1. Consider using a different column for joining if the desired column is consistently null or empty.