sql - Update table with joining another table

Question

I want to set field f1 in table t1 with the value 122 if field f2 in table t2 has value 134. Suppose field f34 is the key between table t1 and t2.
How would I write the query for this in SQL Developer?

Answer 1

你可以试试这个（对于 Oracle）：

UPDATE ( SELECT t1.f1, t2.f2
           FROM t1 
           JOIN t2
             ON t1.f34 = t2.f34
          WHERE t2.f2 = 134
       )
SET f1 = 122;

看到这个 SQLFiddle

对于其他 RDBMS，请尝试使用 join 进行更新

对于 SQL Server：

UPDATE t1 
SET    f1 = 122
FROM   t1 
       JOIN t2  
         ON t1.f34 = t2.f34
WHERE  t2.f2 = 134

看到这个 SQLFiddle

对于 MySQL

UPDATE t1 temp1
  JOIN t2 temp2
    ON temp1.f34 = temp2.f34
SET    temp1.F1 = 122
WHERE  temp2.f2 = 134;

看到这个 SQLFiddle

Answer 2

update t1
set f1 = 122
where exists (select 1 from t2 where f34 = t1.f34 and f2 = 134)

Answer 3

update t1 a,t2 b set a.f1='122' where a.f34=b.f34 and b.f2=134;