从mysql表中选择行和最大值

Question

$query = mysql_query("SELECT * 
                     FROM farm_flocks 
                     WHERE Client_Id='" .$_SESSION["id"] . "' 
                     THEN 
                     SELECT Flock_id in (
                           select max(Flock_id) from 
                           farm_flocks
                     )", $connection);

        if (mysql_num_rows($query) == 1) {

            $row = mysql_fetch_assoc($query);

            //do some stuff

        }

Trying to select all the rows that have the same client Id then after that narrow it the selection down to 1 row by selecting the highest value from the Flock_id column.

Answer 1

Change your query as follows.

$query = mysql_query("SELECT *, max(Flock_id) AS Max_Flock_id FROM farm_flocks WHERE Client_Id='" .$_SESSION["id"] . "')", $connection);

Also, mysql_* is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used.