help deleting obsolete records

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help deleting obsolete records

От:
Frank Bax <fbax@sympatico.ca>
Дата:
I don't know how to write an SQL for the following:

Table "teamwork"
  Attribute |           Type       |  Modifier
-----------+----------------------+-------------
  team      | character varying(8) | not null
  emp       | character varying(2) | not null

Table "timesheet"
  Attribute |           Type           |  Modifier
-----------+--------------------------+-------------
  emp       | character varying(8)     | not null
  team      | character varying(2)     | not null
  lo_shift  | timestamp with time zone |
  hi_shift  | timestamp with time zone |

Consider a subset of data from timesheet which meets the condition:
         lo_shift > (now()-'30days'::interval)
Now I want to delete all rows from teamwork where the data pair "emp,team" 
is *not* in the subset of data retrieved from timesheet.  It is possible 
that timesheet will contain multiple rows for any given emp,team pair.

Frank

Re: help deleting obsolete records

От:
Frank Bax <fbax@sympatico.ca>
Дата:
At 03:28 PM 10/15/02, Frank Bax wrote:
>I don't know how to write an SQL for the following:
>
>Table "teamwork"
>  Attribute |           Type       |  Modifier
>-----------+----------------------+-------------
>  team      | character varying(8) | not null
>  emp       | character varying(2) | not null
>
>Table "timesheet"
>  Attribute |           Type           |  Modifier
>-----------+--------------------------+-------------
>  emp       | character varying(8)     | not null
>  team      | character varying(2)     | not null
>  lo_shift  | timestamp with time zone |
>  hi_shift  | timestamp with time zone |
>
>Consider a subset of data from timesheet which meets the condition:
>         lo_shift > (now()-'30days'::interval)
>Now I want to delete all rows from teamwork where the data pair "emp,team" 
>is *not* in the subset of data retrieved from timesheet.  It is possible 
>that timesheet will contain multiple rows for any given emp,team pair.


Amazing what 24hrs can do..  Is combining emp & team the only way to do 
this, as in:

DELETE  FROM  teamwork  WHERE  emp||':'||team  NOT IN  ( 
SELECT  DISTINCT  emp||':'||team  FROM  timesheet    WHERE   lo_shift > 
(now()-'30days'::interval) );

Frank
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