sql - multi-row update table with "different" data -

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i think best way explain tell have.

i have 2 tables , b both have columns field1 , field2. field 2 not populated in table b

i want populate field 2 of table b field 2 of table field 1 of table matches field 1 of table b.

something update tableb set field2 = tablea.field2 tablea.field1 = tableb.field1.

the reason may seem odd , obscure i'm tyring inital data load form old database new one.

please let me know if need clarification

it sounds need correlated update

update tableb b    set field2 = (select a.field2                    tablea                   a.field1 = b.field1 )  exists( select 1                  tablea                 a.field1 = b.field1 );

since every field2 in b null begin with, may able skip exists (in case rows in b don't have match in updated null generating bit of redo). want include update rows there match.


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