PHP: SELECT ing 2 tables?
I have a activities page and a statusmessages page for each user.
In activities it contains what the users have done, such as being friends with someone, commented on pictures and so.
users_activities
id | uID | msg | date
In 开发者_如何学Gousers_statusmessages, I got the statusmessages, the user creates.
users_statuses
id | uID | message | date
uID is the user´s id.
Now i would like to select both of them and while{} them in one. Where they get sorted by date desc ( as the date in both tables is UNIX timestamp).
So something like WHERE uID = '$userID' ORDER BY date DESC
So example of how i wish it to look:
User: Today is a good day (message) (date: 1284915827) (users_statuses)
User have added as Jack as friend (msg) (date: 1284915811) (users_activities)
User: I have a hard day today (message) (date: 1284915801) (users_statuses)
User have commented on Jacks picture (msg) (date: 1284915776) (users_activities)
How should i do this the right way?
You need to use the UNION operator:
SELECT ua.msg,
ua.date,
'activity' AS is_table
FROM USERS_ACTIVITIES ua
WHERE ua.uid = '{$userID}'
UNION ALL
SELECT us.message,
us.date,
'status'
FROM USERS_STATUSES us
WHERE us.uid = '{$userID}'
ORDER BY `date`
UNION
UNION
removes duplicates. UNION ALL
does not remove duplicates, and is faster for it.
But the data types at each position in the SELECT must match. In the query provided, you can see that the date column is referenced in the second position. You'd get an error if the column order were reversed between the first and second query.
The ORDER BY is applied to the result of the UNION'd query in standard SQL. In MySQL, that includes the LIMIT
clause. But MySQL also supports putting brackets around the UNION'd queries so you can use ORDER BY & LIMIT before the queries are UNION'd.
You're going to want to use a union
http://dev.mysql.com/doc/refman/5.0/en/union.html
This is untested...
(SELECT uID, msg as message, date from users_activities)
UNION
(SELECT uId, message, date from users_statuses) order by date desc limit 20
There are a lot more examples on that page
Something like this would do
SELECT act.*,status.* FROM users_activities act, users_statuses status WHERE act.id = status.id AND status.id = '$UID' ORDER BY status.date,act.date DESC LIMIT 30
Spaced out for visual purposes:
SELECT
act.*,status.*
FROM
users_activities act,
users_statuses status
WHERE
act.id = status.id
AND
status.id = '$UID'
ORDER BY
status.date,act.date DESC
LIMIT
30
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