[Qgis-user] Edit attribute table rows

[Neumann, Andreas]

Hi Lester, 

The field calculator is meant to change "a lot" of values. It will
update all selected records with the new value or calculation
(expression). 

With CASE WHEN END you can introduce switches for different rules. 

So - please don't export to Excel. You can do it all with the field
calculator. 

Andreas 

On 2016-04-08 15:28, Lester Anderson wrote:

> Hi Andreas,
> 
> I am trying change a lot of values, if it was a few that is no problem.
> 
> The other option is to export the attribute table as a database and
> edit in Excel etc and then join the table in QGIS
> 
> Cheers
> Lester
> 
> On 8 April 2016 at 14:23, Neumann, Andreas <a.neumann at carto.net> wrote: 
> 
>> Hi Lester,
>> 
>> I thought you want to set the value to 623 where the value was NULL before?
>> - so just write 623 in the left field after you selected the values.
>> 
>> Alternatively, you can do without the previous selection and use the
>> following expression.
>> 
>> CASE WHEN depth IS NULL THEN 623 ELSE depth END
>> 
>> Hope this helps,
>> 
>> Andreas
>> 
>> On 2016-04-08 15:13, Lester Anderson wrote:
>> 
>> Hello Andreas,
>> 
>> Selecting the rows where depth = NULL is fine. The field calculator
>> does not update the depth with the depth where known values are
>> present.
>> 
>> Only update selected features is checked, update existing field
>> checked, with output field set to depth:
>> Expression: tried just "depth" and also "depth"="depth".
>> 
>> Have I missed something here?
>> 
>> Thanks
>> 
>> On 8 April 2016 at 12:30, Neumann, Andreas <a.neumann at carto.net> wrote:
>> 
>> Sure.
>> 
>> It is a two-step thing:
>> 
>> 1. Select all records where Depth IS NULL. Use the "Select Features using an
>> expression" button (the Epsilon sign) for that and "depth IS NULL" as an
>> expression
>> 
>> 2. Use the field calculator and only update the selected records (the top
>> checkbox in the field calculator).
>> 
>> You can find details about the field calculator in the QGIS manual.
>> 
>> Hope this helps,
>> 
>> Andreas
>> 
>> On 2016-04-08 13:18, Lester Anderson wrote:
>> 
>> Hello,
>> 
>> I have an attribute table of earthquake data (focal mechanism beach
>> balls) and need to edit the depth attribute. Each ball is defined by
>> two rows in the table, eg first ball
>> 
>> Row_ID Strike Dip Rake Magnitude Quadrant Depth
>> ----------------------------------------------------------
>> 0 NULL NULL NULL NULL Tensional and Compressional NULL
>> 1 233 38 -96 6.77 Compressional 623
>> 2 NULL NULL NULL NULL Tensional and Compressional NULL
>> 3 68 36 83 5.7 Compressional 39
>> etc
>> 
>> where rows 0,1 and 2,3 represent separate beach balls, so basically it
>> is a row calculation
>> 
>> What I need to do is replace the Depth NULL value with the depth 623
>> etc for each entry. Is there an easy way of doing this?
>> 
>> Thanks
>> 
>> Lester
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