I have some tables with various content. What I want to accomplish is to display the lets say 20 latest entries from those tables in a div.
Here is my first table - audio1
userID folder title date
the two other folders look exactly the same
audio2
userID folder title date
audio3
userID folder title date
How can I get the data from all the tables at the same time and echo them one by one to a div ordered by date with PHP?
SELECT userID, folder, title, date
FROM audio1
UNION ALL
SELECT userID, folder, title, date
FROM audio2
UNION ALL
SELECT userID, folder, title, date
FROM audio3
ORDER BY date DESC LIMIT 20;
Your SQL query will be a 3 part UNION
. A UNION
query concatenates results from multiple tables with (usually) similar structures, when a JOIN
relationship is not needed but rather you just need to return rows from multiple tables.
$sql = "SELECT userID, folder, title, date FROM audio1
UNION ALL
SELECT userID, folder, title, date FROM audio2
UNION ALL
SELECT userID, folder, title, date FROM audio3
LIMIT 20;";
$result = mysql_query($sql);
if ($result) {
// Fetch results and echo them into a list.
}
You will need a column to ORDER BY
. This is likely to be date
, but you may have other plans. Add an ORDER BY
clause before the LIMIT 20
.
看来您的数据库设置是错误的,您只需要一个名为“ audio”的表,其中一个字段表示表名中当前正在使用的数字。
You may try the union, or you can try a join.
SELECT
COALESCE(t1.userID, t2.userID, t3.userID) as userID
, t1.folder, t1.title, t1.date
, t2.folder, t2.title, t2.date
, t3.folder, t3.title, t3.date
FROM table1 t1
FULL OUTER JOIN table2 t2 ON (t1.userID = t2.userID)
FULL OUTER JOIN table3 t3 ON (t1.userID = t3.userID)
It's a very different beast, so I'd thought I'd give you the option.
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