通过自我加入进行更新

Oracle不支持

JOIN

UPDATE

用这个：

MERGEINTO    contactassociations ca1USING   contactassociations ca2ON      (        ca1.contactid = ca2.contactid        AND ca1.entitytable = 'EMPLOYER'        AND  ca2.entitytable = 'CLIENT'        )WHEN MATCHED THENUPDATESET     parentid = ca2.id