MySQL - Update values based on subquery

问题:

let's say I have select, which return me from table1:

ID  Name
 1  Bob
 2  Alice
 3  Joe

Then I want UPDATE values in another table based on this result:

UPDATE table2 SET Name = table1.Name WHERE ID = table1.ID

As I understood, I can only do internal select in one place, like:

UPDATE table2 SET Name = (select Name from table1) WHERE ...

And I don't know how to specify WHERE-condition.

回答1:

all you should do is just join the tables like this.

UPDATE table2 t2
JOIN table1 t1 ON t1.id = t2.id
SET t2.name = t1.name;

RESULTS WITH JOIN

if you are set on doing it with a select you could do it like this.

UPDATE table2 t2,
(   SELECT Name, id 
    FROM table1 
) t1
SET t2.name = t1.name
WHERE t1.id = t2.id

RESULTS FROM SELECT

回答2:

 UPDATE table2
 SET name = (SELECT table1.Name FROM table1 WHERE table1.id = table2.id)
 WHERE apply_condition

EDIT:#1

   UPDATE table2 t2, (SELECT id, name FROM table1) t1 SET t2.name = t1.name WHERE t1.id = t2.id

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回答3:

Try this

Update table2
Set Name = (Select Name From table1 where table1.ID = table2.ID)
Where table2.ID In (Select ID From table1)