Oracle multiple processes updating same table marriage and dating statistics
Consequently, to prevent this, you might do this: One potential issue may arise when the subquery actually finds more than one matching row in tbl B.If this happens, the UPDATE will terminate with an error ("subquery may return only one row").
select * from student; ID NAME SCORE ---------- --------------- ---------- 1 Jack 540 2 Rose 3 William 650 4 Caledon 620 5 Fabrizio 600 6 Thomas 7 Ruth 690 11 Brock 705 10 Lizzy 9 Wallace 600 8 Spicer 620 11 rows selected. But it does not work with a merge query (probably because of the update part): “Missing IN or OUT parameter at index:: 1” Would would you advise to retrieve the value of a field (typically an id) of the row that has been inserted or updated?Oracle’s MERGE statement is tailor-made for situations when you want to do an "upsert" i.e.update existing rows in a table or insert new rows depending on a match condition.This is typically the case when you have to synchronize a table periodically with data from another source (table/view/query).In place of 3 separate unwieldy INSERT, UPDATE and DELETE statements with conditional sub-queries, the all-in-one MERGE does the job in one shot.
works fine when I try to update all the records in tbl A, however, in this case I only have missing data which I have identified and populated in tbl B.