While not null sql

Thomas: Oracle didn't support! My belief is MySQL is similar, starting support in 4. That would seem to suggest that! Don't have my hands on new specs so I can't say for sure. Or in other words, is it guaranteed to always return 0 rows, no matter if MyColumn is nullable in the database or not? It should also be noted that because! Show 4 more comments. NULL has no value, and so cannot be compared using the scalar value operators.

Barry Brown Barry Brown I wasn't suggesting that this is a Microsoft only behavior. Out of interest, are there any situations where this expected behaviour is useful?

It just seems to me having 'a'! I'd have thought "some value compared to no value" would always be "not equal", but maybe that's just me?!? I think it's interesting that people describe NULL as ' having no value '. Similar, then, to saying the number 1 'has a value' when it actually is a value. But NULL represents non-value.. Show 1 more comment. Note that this behavior is the default ANSI behavior. Cade Roux Cade Roux IMHO, this last statement seems a little odd in it's exclusion of nulls from the results!

Avoid using this feature in new development work, and plan to modify applications that currently use this feature. This is the code that brought me here: where a!

Hrvoje Batrnek Hrvoje Batrnek 4 4 silver badges 15 15 bronze badges. Untold bugs and work arounds because code is not permitted to handle nulls in a reasonable manner.

I totally agree with this sentiment. Jeff Mergler Jeff Mergler 1, 14 14 silver badges 20 20 bronze badges. This is the best workaround, just be careful in the few cases where an empty string vs. In this scenario, the loop runs endlessly and never ends. Now, we will realize this scenario with the help of the following example. We need to take account of one thing that we should not forget to cancel the execution of the query manually:. In the following flowchart, it is obvious that the value of the variable never changes; therefore, the loop never ends.

The reason for this issue is that the variable is always equal to 1 so the condition returns true for each iteration of the loop:. In this example, we have checked the value of the variable, and when the value is equal or greater than 7, the code entered the IF…ELSE block and executed the BREAK statement, and so it exited the loop immediately.

For this reason, the message shows the values of the variable up to 7. In the following example, we will check whether the variable value is odd or even. The output is as follows:. In the output, you can see all the records from the Cars table, printed in sets of two on the console. In the script above, the while loop executes until the value of the count variable remains less than or equal to The initial value of the count variable is 1.

In the body of the loop, the value of the remainder of the count divided by 2 is stored in the mod variable. If the value of the count variable is odd, the remainder will be 1, and if the remainder is 0, the CONTINUE statement is used to shift the control back to the start of the while loop and the value of the count variable is not printed.

Otherwise, the value of the count variable is printed on the console. Here is the output of the above script:. The while loop in the following script will terminate after printing the first five integers:. WHILE condition. END ;. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use , cookie and privacy policy. Copyright by Refsnes Data.

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