如何从其他表列的SUM结果更新列？

Question

What im looking for is to update a column from table 1 using the results from the SUM of a different column in table 2 for example :

table 1

id             | views | 
--------------------
1          |   0  |  
2          |   0  |  

table 2

show_id    | views | 
--------------------
1          |   5   |  
1          |   10  |  
1          |   10  |  
2          |   10  |  
2          |   10  |  
2          |   10  |  

Now the two tables are connected by id and show_id there the same value; what i want is to add the sum of views from show_id to id where show_id=id

so at the end table 1 should look like these :

id         | views | 
--------------------
1          |   25  |  
2          |   30  |  

I'm using MySQL 5.1.30

Answer 1

Use an update with join :

UPDATE table1 t1
INNER JOIN table2 t2 ON (t1.id = t2.show_id)
SET t1.views = SUM(t2.views)
GROUP BY t1.id;

See: http://dev.mysql.com/doc/refman/5.0/en/update.html