PostgreSQL Record Reordering using Update with a Sub-Select

Question

I found this solution on the SQL Server forum on how to reorder records in a table.

UPDATE SomeTable
SET rankcol = SubQuery.Sort_Order
FROM
    (
    SELECT IDC         


        

Answer 1

You don`t need to explicitly join SomeTable, how cool is that? :)

UPDATE SomeTable
SET rankcol = SubQuery.Sort_Order
FROM
    (
    SELECT IDCol, Row_Number() OVER (ORDER BY ValueCOL) as SORT_ORDER
    FROM SomeTable
    ) SubQuery
where SubQuery.IDCol = SomeTable.IDCol

remark: Postgres is case insensitive, better use lower-case, like row_number, sort_order, id_col , etc.