Re: Selecting newly added column returns empty but only when selecting with other columns in table

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От mrtruji
Тема Re: Selecting newly added column returns empty but only when selecting with other columns in table
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Msg-id CAJEV4po_qzuEwBByE=bQbtma66B=x_tx6uSVoB0ybhCdSnURfA@mail.gmail.com
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Ответ на Re: Selecting newly added column returns empty but only when selecting with other columns in table  (John R Pierce <pierce@hogranch.com>)
Ответы Re: Selecting newly added column returns empty but only when selecting with other columns in table  (John R Pierce <pierce@hogranch.com>)
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Used psycopg2 in python to create and fill in the table with the code below: 

cur.execute('alter table data add features_bin bytea;')

for x in features:
   cur.execute('insert into data (features_bin) values (%s);',[x])
   conn.commit()

features is a list variable of binary array objects. 

On Thu, Nov 26, 2015 at 7:04 PM, John R Pierce <pierce@hogranch.com> wrote:
On 11/26/2015 4:13 PM, mrtruji wrote:

Just added a new bytea type column to an existing psql table and populated the column entirely with row data. Running into some strange query results:

 When I select the newly added column by itself I get all the data as expected:.....


can you show the SQL commands you used to add this column and populate it?   if you used INSERT to populate the new column, that would have inserted NEW rows, not modified existing rows.  to modify the existing rows, you need to use UPDATE with a WHERE clause that selects the correct row to UPDATE with the data for your new field...



--
john r pierce, recycling bits in santa cruz



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