I have two databases. One is called INFO
with three tables ( Stories
, Comments
, Replies
)
Stories
has the following fields
+--------------+----------------+------+-----+---------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+----------------+------+-----+---------------------+-----------------------------+
| storyID | int(11) | NO | PRI | NULL | |
| originalURL | varchar(500) | YES | | NULL | |
| originalDate | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| numDiggs | int(11) | YES | | NULL | |
| numComments | int(11) | YES | | NULL | |
| diggURL | varchar(500) | YES | | NULL | |
| rating | varchar(50) | YES | | NULL | |
| title | varchar(200) | YES | | NULL | |
| summary | varchar(10000) | YES | | NULL | |
| uploaderID | varchar(50) | YES | | NULL | |
| imageURL | varchar(500) | YES | | NULL | |
| category1 | varchar(50) | YES | | NULL | |
| category2 | varchar(50) | YES | | NULL | |
| uploadDate | timestamp | NO | | 0000-00-00 00:00:00 | |
| num | int(11) | YES | | NULL | |
+--------------+----------------+------+-----+---------------------+-----------------------------+
Another database is called Data
with one table ( User
). Fields shown below:
+-------------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------------+-------------+------+-----+---------+-------+
| userID | varchar(50) | NO | PRI | NULL | |
| numStories | int(11) | YES | | NULL | |
| numComments | int(11) | YES | | NULL | |
| numReplies | int(11) | YES | | NULL | |
| numStoryDiggs | int(11) | YES | | NULL | |
| numCommentReplies | int(11) | YES | | NULL | |
| numReplyDiggs | int(11) | YES | | NULL | |
| numStoryComments | int(11) | YES | | NULL | |
| numStoryReplies | int(11) | YES | | NULL | |
+-------------------+-------------+------+-----+---------+-------+
User.userID
is full of thousands of unique names. All other fields are currently NULL
. The names in User.userID
correspond to the names in Stories.uploaderID
.
I need to, for each userID
in User
, count the number of stories uploaded from (ie num) Stories
for the corresponding name and insert this value into User.numStories
.
The query which I have come up with (which produces an error) is:
INSERT INTO DATA.User(numStories)
SELECT count(num)
FROM INFO.Stories
WHERE INFO.Stories.uploaderID=DATA.User.userID;
The error I get when running this query is
Unknown column 'DATA.User.userID' in 'where clause'
Sorry if this is badly explained. I will try and re-explain if need be.
You aren't creating new entries in the User
table, you're updating existing ones. Hence, insert
isn't the right syntax here, but rather update
:
UPDATE DATA.User u
JOIN (SELECT uploaderID, SUM(num) AS sumNum
FROM INFO.Stories
GROUP BY uploadedID) i ON i.uploaderID = u.userID
SET numStories = sumNum
EDIT:
Some clarification, as requested in the comments. The inner query sums the num
in Stories
per uploaderId
. The updates
statement updates the numStories
in User
the the calculated sum of the inner query of the matching id .
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