Comments on: Why NULL never compares false to anything in SQL http://www.xaprb.com/blog/2006/05/18/why-null-never-compares-false-to-anything-in-sql/ Stay curious! Fri, 29 Aug 2008 19:44:29 +0000 http://wordpress.org/?v=2.2.2 By: Xaprb http://www.xaprb.com/blog/2006/05/18/why-null-never-compares-false-to-anything-in-sql/#comment-4311 Xaprb Thu, 22 Feb 2007 15:13:17 +0000 http://www.xaprb.com/blog/2006/05/18/why-null-never-compares-false-to-anything-in-sql/#comment-4311 <p>For a row where <code>increment</code> is null, your query becomes:</p> <p><code>select * from employee where NULL = 500;</code></p> <p><code>NULL = 500</code> is never true, so the row will not be returned.</p> <p>(It is never false either, as I explain above. It is unknown.)</p> <p>If you want rows where the column is either 500 or NULL, try this:</p> <p><code>select * from employee where increment is null or increment = 500;</code></p> For a row where increment is null, your query becomes:

select * from employee where NULL = 500;

NULL = 500 is never true, so the row will not be returned.

(It is never false either, as I explain above. It is unknown.)

If you want rows where the column is either 500 or NULL, try this:

select * from employee where increment is null or increment = 500;

]]> By: vinay http://www.xaprb.com/blog/2006/05/18/why-null-never-compares-false-to-anything-in-sql/#comment-4303 vinay Thu, 22 Feb 2007 14:15:52 +0000 http://www.xaprb.com/blog/2006/05/18/why-null-never-compares-false-to-anything-in-sql/#comment-4303 <p>Hi, In a query i am comparing the values of a column with some hard coded value in where clause.will the row in the table which has a null value in the field being compared be returned? Eg: Select * from Employee where increment = 500; If in a row the increment is null than that row will come in output or not?</p> Hi,
In a query i am comparing the values of a column with some hard coded value in where clause.will the row in the table which has a null value in the field being compared be returned?
Eg:
Select * from Employee where increment = 500;
If in a row the increment is null than that row will come in output or not?

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