How do you handle NULL values in SQL Server?

Methods for handling NULL values in SQL Server include:

  1. Use the IS NULL and IS NOT NULL operators to determine if a value is NULL.
    For example:
    SELECT * FROM table_name WHERE column_name IS NULL;
  2. Replace NULL values with a specified default value using the COALESCE function. For example: SELECT COALESCE(column_name, ‘default_value’) FROM table_name;
  3. Utilize a CASE statement to handle NULL values, deciding what value should be taken based on certain conditions. For example: SELECT CASE WHEN column_name IS NULL THEN ‘default_value’ ELSE column_name END FROM table_name;
  4. Use the IFNULL function to replace NULL values with a specified default value.
    For example:
    SELECT IFNULL(column_name, ‘default_value’) FROM table_name;
  5. Use the NULLIF function to replace a specified value with NULL.
    For example:
    SELECT NULLIF(column_name, ‘value_to_replace’) FROM table_name;

By using the above method, NULL values encountered in SQL Server can be effectively handled.

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