Corresponding relations between two tables as follows: the parent table of Fid parentid for the child table, and as a one-to-many relationship, more than a Fid corresponding parentid, according to the corresponding relationship to the parent table M field value of the update to the child table FM in
The update child table set FM=
(select arjun from the parent table a inner join child table b on b. m=arjun) where FM is null
Will be prompted to ORA - 01427 single subquery return multiple rows, and rownum=1 is not an error, but the child table FM value is still empty, has not been updated, please advise!

CodePudding user response:

Update zi t1 set t1. FM=(select v1. M from fu v1 where t1. Parentid=v1. Fid)

CodePudding user response:

The update child table a FM=(select m from the parent table b where Amy polumbo arentid=b. id and rownum<2)
Where Amy polumbo arentid (select fid in the from the parent table)