Re: Use ctid in where clause in update from statement

This is just a very simplified sample and doesn’t makes sense, but it shows the execution plan. The original query is more complex.  It selects more values and updates more columns.

Dirk

 

UPDATE test_large d

   SET grp = s.grp

  FROM (SELECT ctid, test_large.*

          FROM test_large

         WHERE grp = 1) s

 WHERE d.ctid = s.ctid;

 

Besides, what the above does is select for rows that have grp=1 and then set grp to the same value.

 

BR

Dirk

 

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