[SQL] UPDATE in a specific order

[Luiz K. Matsumura]

Hi,

I have a follow scenario:
CREATE TABLE table1 (
  id integer
, vlpr numeric(10,2)
, vlab numeric(10,2)
, vlbx  numeric(15,5)
, pct  numeric(12,8)
);

CREATE TABLE table2 (
  id integer
,  fk_table1 integer
, tpop char(2)
,  valor  numeric(15,5)
);

insert into table1  VALUES ( 1, 200 , 0 , 0 , 1 );

insert into table2  VALUES
  ( 1, 1 , 'CR'  ,   100  )
, ( 2, 1 , 'BX'  ,     15  )
, ( 3, 1 , 'AC'  ,     40  );

I need to make update of table1 with data on table2 in the order of id 
of table2

I´m trying to do an update like this:

UPDATE table1
SET  vlab = vlab + CASE WHEN tHist.tpop IN ('BX' , 'DC')
            THEN - tHist.valor
           ELSE tHist.valor
           END
   , vlbx = vlbx + CASE WHEN tHist.tpop IN ('BX', 'DC')
                        THEN tHist.valor
                   ELSE 0
                   END
   , pct = CASE WHEN tHist.tpop in ('AC',  'DC' )
                THEN (vlpr - vlbx) / vlab
           ELSE pct
           END
FROM  ( SELECT * FROM table2 ORDER BY id  ) tHist
WHERE table1.id = tHist.fk_table1


The "FROM ( SELECT * FROM table2 ORDER BY id  ) tHist"  is a try to 
force a specific order on table2 to update table1
but this isn´t working.

There are some way to do this with a UPDATE statement ?

Thanks in advance,

--
Luiz K. Matsumura
Plan IT Tecnologia Informática Ltda.
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