CASE with no ELSE

Question

CASE with no ELSE

Accepted Answer

When CASE has no ELSE and no WHEN condition matches, the result is NULL. Bob's dept is 'Sales', not 'Eng', so none of the WHEN branches match and CASE returns NULL. This is different from an error - it is valid SQL. However, NULL in unexpected places can cause bugs downstream, so it is usually clearer to include an explicit ELSE.