Submitted on: 5/19/2002 9:44:16 AM By: the_firm
Level: Beginner User Rating:
By 6 Users Compatibility:PHP 4.0
Users have accessed this code 1162 times.
how to do subselects in mySQL
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//**************************************
//
// Name: sub select for mySQL
// Description:how to do subselects in m
// ySQL
// By: the_firm
//
//This code is copyrighted and has // limited warranties.Please see http://
// www.Planet-Source-Code.com/xq/ASP/txtCod
// eId.629/lngWId.8/qx/vb/scripts/ShowCode.
// htm //for details. //**************************************
//
$query = "CREATE TABLE tmp
SELECT my_id
FROM table1
WHERE myvalue is null
";
mysql_query ($query);
$query = "SELECT sec_id, info
FROM table2
LEFT JOIN tmp
ON sec_id = my_id
WHERE sec_id NOT IN(my_id)
";
$result=mysql_query ($query);
mysql_query ("DROP TABLE tmp");
while ($row = mysql_fetch_array ($result)) {
echo $row["sec_id"]."\n";
echo $row["info"]."\n";
}
This code will fail when there are many
users on a website. Suppose one of them
does DROP TABLE tmp; while another
executes SELECT blah LEFT JOIN tmp just
after that?
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