SQL using If Not Null on a Concatenation

Question

If I have the table

SELECT (Firstname || \'-\' || Middlename || \'-\' || Surname)  AS example_column
FROM example_table

This will

Answer 1

• The NULLIF expression reduces blank Middlename to NULL
• Concatenating '-' with a NULL will always return NULL
• TheVALUE expression replaces NULLs with an empty string

_

SELECT Firstname || VALUE( '-' || NULLIF('Middlename',''),'') || '-' || Surname'  
       AS example_column
FROM example_table