UPDATE statement syntax

Question

I seem to have the most problem with UPDATE statement syntax. The following select works fine:
select * from rco.rpt_ds1_cnt_cat c, rco.rpt_ds1_valid_per_lerg l
where l.loc = c.aloc;
All I want to do, and preferably with aliases is set c.aloc = l.loc. Every imaginable syntax is coming up with errors, either invalid columns or SET word missing, etc.
Can someone tell me how to word this?

Answer 1

You need to be aware that id there is a record in rpt_ds1_cnt_cat that does not have a matching record in rpt_ds1_valid_per_lerg this statement will update aloc_valid to NULL. If that is not what you are looking for, then you need to add a predicate like:
UPDATE rpt_ds1_cnt_cat C
SET aloc_valid = (SELECT DISTINCT validperlerg
                  FROM rpt_ds1_valid_per_lerg l
                  WHERE l.loc = c.aloc)
WHERE c.aloc IN (SELECT loc FROM rpt_ds1_valid_per_lerg)
or
UPDATE rpt_ds1_cnt_cat C
SET aloc_valid = (SELECT DISTINCT validperlerg
                  FROM rpt_ds1_valid_per_lerg l
                  WHERE l.loc = c.aloc)
WHERE EXISTS (SELECT 1
              FROM rpt_ds1_valid_per_lerg l
              WHERE l.loc = c.aloc)If loc is the PK of rpt_ds1_valid_per_lerg, or is constrained unique, then you could also update a join, which is what I think you were trying for originally.
Something like:
UPDATE (SELECT c.aloc_valid, l.validperlerg
        FROM rpt_ds1_cnt_cat c, rpt_ds1_valid_per_lerg l
        WHERE l.loc = c.aloc)
SET aloc_valid = validperlergHTH
John