php - Mysql 获取数组查询？

Question

我正在使用 php 查询通过 mysql_fetch_array 从 mysql 数据库检索信息，并使用返回的结果查询另一个数据库？我很新手。这可能吗？

$search =
"SELECT `a`,`b`

FROM 'DB'
WHERE `x` LIKE '$var'
LIMIT 0 , 30";

$result = mysql_query($search, $connection);
if($result){

while ($row = mysql_fetch_array($result)){
echo $row["a"]." ".$row["b"]."<br />";
                        }
} else {
echo "<p> Subject search failed. <p>";
echo "<p>" . mysql_error() . "</p>";
    }

<!-- SECOND QUERY -->   
$search2 = 
"SELECT `a`,`b`
FROM `DB`
WHERE `x` = **$row['a']**  *trying to grab the result from the first query and use as search query in second?*

LIMIT 0 , 100";

$result2 = mysql_query($search2, $connection);
if($result2){

while ($row2 = mysql_fetch_array($result2)){
echo $row2["a"]." ".$row2["b"]."<br />";
                        }
} else {
echo "<p> Subject search failed. <p>";
echo "<p>" . mysql_error() . "</p>";
}

有人能指出我正确的方向吗？

Answer 1

$search = "SELECT <code>a</code>,<code>b</code> FROM <code>DB</code> WHERE <code>x</code> LIKE '$var' LIMIT 0 , 30";
$result = mysql_query($search, $connection);
if($result){
    while ($row = mysql_fetch_array($result)){
        echo $row["a"]." ".$row["b"]." ";
        $search2 = "SELECT <code>a</code>,<code>b</code> FROM <code>DB</code> WHERE <code>x</code> = '".$row['a']."' LIMIT 0 , 100";
        $result2 = mysql_query($search2, $connection);
        if($result2){
            while ($row2 = mysql_fetch_array($result2)) {
                echo $row2["a"]." ".$row2["b"]." ";
            }
        } else {
            echo "Subject search failed.";
            echo mysql_error();
        }
    }
} else {
    echo "Subject search failed. ";
    echo mysql_error();
}