Re: [sqlite] Sorting Question

[caurues]

Thank you Igor!  Now I understand.

Caureus



Igor Tandetnik wrote:
> 
> caurues <caureu...@aol.com> wrote:
>> I am hoping I can get an answer to my question. I want to sort a column
>> in
>> ascending order, but I want null values to sort to the bottom. A simple
>> ORDER BY ColumnA ASC sorts the column in ascending order with null vales
>> appearing on top. The following code, however, works correctly, but I
>> have
>> no idea why: ORDER BY ColumnA IS NULL ASC, ColumnA ASC.
> 
> You are not limited to sorting just by a column name - you can sort by any
> expression. In particular, the expression (ColumnA IS NULL) evaluates to 0
> when the column is not null, and to 1 when it is. Then these zeros and
> ones are sorted in ascending order. This has the net effect of putting
> non-null values first and null values at the end.
> -- 
> Igor Tandetnik
> 
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> 

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[sqlite] Sorting Question

[caurues]

I am hoping I can get an answer to my question. I want to sort a column in
ascending order, but I want null values to sort to the bottom. A simple
ORDER BY ColumnA ASC sorts the column in ascending order with null vales
appearing on top. The following code, however, works correctly, but I have
no idea why: ORDER BY ColumnA IS NULL ASC, ColumnA ASC. Can someone please
explain why? I also tried ORDER BY ColumnA IS NULL ASC and this code sorted
only the null values to the bottom of the remaining unsorted list, which I
do not understand. I guess what I am not understanding is why the result of
filtering within an ORDER BY clause appears at the bottom of my list.
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