> For certain columns i am completely sold on not using nulls, for others, i > cant see any conceptual reason to favor either way, so i thought i'd tap > you all for some insight.
A NULL is the equivalent of saying "I don't know" whereas a 0 means the value between -1 and 1 and a blank means 'no value'. For example... suppose you're recording temperatures at various locations. Atlanta <blank> Boston 0 Chicago null It pretty clear that the temperature in Boston is 0, which is not the same as being empty. The difference between null and blank is a bit more subtle. null means that you don't know what the value is - if the folks in Chicago say that their thermometer is broken, they have reported their results, but their results are "we have no idea how cold it is here". You use a blank in Atlanta until you hear from them, at which time you either have a temperature (an actual number), or you have another "We have no idea how cold it is outside because our thermometer is broken too." which means null again. Does that help? -- Whil Moving to Linux: Freedom, Choice, Security, Opportunity http://www.hentzenwerke.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
