Re: UPDATE Syntax Error

On Fri, February 4, 2011 12:51, Rich Shepard wrote:
> I _think_ today's the worst cold day and my head will clear from now
> on.
> In the meantime, I'm not seeing why an UPDATE statement does not return
> the
> number of updated rows.
>
> The idea is to replace NULL values in the units column with 'mg/L':
>
> jerrittwq=# update monitor set units = 'mg/L' where units = NULL;
> UPDATE 0
>
> and there should be several thousands of updated rows. I've also tried
> specifying the units attribute as '' and ' ' with no better results.
> Should
> be a simple statement and I'm not seeing why it fails.
>
> FWIW, I tried specifying an alias for the table, but that barfed for a
> different reason:
>
> jerrittwq=# update monitor as m set m.units = 'mg/L' where m.units = NULL;
> ERROR: column "m" of relation "monitor" does not exist
> LINE 1: update monitor as m set m.units = 'mg/L' where m.units = NUL...
>
> Clue stick, please,
>
> Rich
>
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Rich,

I believe you want to use units IS NULL; instead of units = NULL; in your
WHERE clause.

Tim
--
Timothy J. Bruce

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