PostgreSQL 10：有了这个 upsert 函数，如何仅在列值不同时更新？

Question

我希望更新 apr 仅当它不同时，现在，无论它是不同还是相同，它似乎都会更新：

   INSERT INTO live_mytable (id, loan_type, apr, term, oldestyear) 
   SELECT id, loan_type, apr, term, oldestyear
   FROM   imp_mytable 
   ON CONFLICT (id,loan_type,term,oldestyear) DO update
   set apr = excluded.apr;

如何将此查询更改为仅在值不同时更新？

Answer 1

您可以在更新中使用 WHERE 子句：

 INSERT INTO live_mytable (id, loan_type, apr, term, oldestyear) 
   SELECT id, loan_type, apr, term, oldestyear
   FROM   imp_mytable 
 ON CONFLICT (id,loan_type,term,oldestyear) 
 DO update
   set apr = excluded.apr
 WHERE 
      live_mytable.apr IS DISTINCT FROM 
      EXCLUDED.apr;

PostgreSQL 10：有了这个 upsert 函数，如何仅在列值不同时更新？

PostgreSQL 10: With this upsert function, how to update only if column value is different?

postgresql

postgresql-10