Defaults

  • kalyani.k478

    Default port

    Points: 1400

    Good, easy question.

  • ScottC91

    SSC Rookie

    Points: 43

    What is the difference between option 1 and option 2? If option one would cause the default to be selected because that column will be null why doesn't manually setting it null cause the same thing?

  • Kenneth.Fisher

    SSCoach

    Points: 19789

    ScottC91 (11/26/2012)


    What is the difference between option 1 and option 2? If option one would cause the default to be selected because that column will be null why doesn't manually setting it null cause the same thing?

    Basically because you are inserting a value. Well the absence of a value really, but you are being specific about what you want in the field.

    Look at it like this. In a nullable column without a user defined default, the default is actually NULL. If you insert a value, even NULL, you are telling SQL that you want that value in the field. If you don't pass in a value (or use the keyword DEFAULT) you are asking for the default.

    Interestingly enough the following code will demonstrate this:

    DECLARE @temp TABLE (temp int null)

    INSERT INTO @temp VALUES (DEFAULT)

    SELECT * FROM @temp

    Note that I don't have a user defined default for the column temp, but when I use the DEFAULT keyword I get a null in the field.

    Hope that helps.

    Kenneth FisherI was once offered a wizards hat but it got in the way of my dunce cap.--------------------------------------------------------------------------------For better, quicker answers on T-SQL questions, click on the following... http://www.sqlservercentral.com/articles/Best+Practices/61537/[/url]For better answers on performance questions, click on the following... http://www.sqlservercentral.com/articles/SQLServerCentral/66909/[/url]Link to my Blog Post --> www.SQLStudies.com[/url]

  • asifkareem

    Ten Centuries

    Points: 1089

    Good and Easy One.

    Thansk:hehe:

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