sql [sql]如何从另一个表中的相应数据更新一个表中的数据

Posted 2021-05-14

UPDATE MatchupResults 
SET PollID = MI.PollID 
FROM MatchupItems MI 
WHERE MatchupResults.SelectedID = MI.ID

-- loops thru MatchupItems table, 
-- grabs the pollid from it
-- updates the MatchupResults table with the corresponding pollid.
-- MatchupResults.SelectedID is the foreign key to the MatchupItems ID column.
-- (need to manually create new column PollID on MatchupResults table.)