Question

Hi i have tables like this :

table entry :

id | total_comments
_____________________
1 | 0
2 | 0
3 | 0
4 | 0

table comments :

id | eid | comment
_____________________
1 | 1 | comment sdfd
2 | 1 | testing testing
3 | 1 | comment text
4 | 2 | dummy comment
5 | 2 | sample comment
6 | 1 | fg fgh dfh

Query i write :

UPDATE entry 
   SET total_comments = total_comments + 1 
 WHERE id IN ( SELECT eid 
                 FROM comments 
                WHERE id IN (1,2,3,4,5,6))

Results i get is :

table entry :

id | total_comments
_____________________
1 | 1
2 | 1
3 | 0
4 | 0

Expected results :

table entry :

id | total_comments
_____________________
1 | 4
2 | 2
3 | 0
4 | 0

Any help will be appreciated.

Answer 1

Use:

UPDATE entry 
   SET total_comments = (SELECT COUNT(*)
                           FROM COMMENTS c
                          WHERE c.eid = id
                       GROUP BY c.eid)
 WHERE id IN ( SELECT eid 
                 FROM comments 
                WHERE id IN (1,2,3,4,5,6))