What I Learned About SQL on August 7, 2004

February 8, 2004 | No comments

What I Learned About SQL on August 7, 2004
(File under: Posts that were meant to be but never were)

  1. COALESCE – the ANSI standard
  2. ISNULL – the Microsoft T-SQL standard (only takes two values)
  3. IFNULL – the MySQL standard (only takes two values)
  4. NVL – Oracle / Informix PL/SQL standard (only takes two values)
Got that from a message board.

Basically it takes a query result, and in order of the parameters, if the first is NULL, then it uses the second parameter (often a string or N/A or whatever.

SQL Server: Coalesce()

SQL Server: Isnull()

Kind of useful when you want to munge strings because anything + NULL is always null, you can avoid that by doing

COALESCE+ ‘anything