PHP / MySQL多重查询

Question

哎呀，我的解析错误出在哪里。 我在第一个查询中输入了分号。

因此，基本上我想在同一PHP脚本中使用三个不同的select语句进行查询。 这可能吗？ （我保证的最后一个问题是，在此之后，我认为基础知识可以使我花上几周的时间而不必多问）

<?php
include("server_connect.php");

mysql_select_db("rnissen");

$query = "SELECT column_one, column_two, column_four FROM tbltable;"

$results = mysql_query($query) or die(mysql_error());

$querytwo = "SELECT column_one, column_two, column_five FROM tbltable WHERE column_five = 1989";

$results = mysql_query($querytwo) or die(mysql_error());

$querythree = "SELECT COUNT(column_five) FROM tbltable WHERE column_five = 1989";

$results = mysql_query($querythree) or die(mysql_error());

?>  

第二部分好，所以我按照建议更改了代码，并尝试将其添加到表中。 我仍然收到解析错误：语法错误，第7行的C：\\ xampp \\ htdocs \\ 3718 \\ assign5SELECT.php中出现意外的'$ results1'（T_VARIABLE）

我试过没有表，它仍然是相同的错误。 我有什么想念的吗？ 这是带有新变量的更新代码。

mysql_select_db("rnissen");

$query = "SELECT column_one, column_two, column_four FROM tbltable;"
$results1 = mysql_query($query) or die(mysql_error());
echo "Column One, Column Two, Column Four : </br>";
echo "<table border=\"1\">\n";
while ($row1 = mysql_fetch_assoc($results1)) {
echo "<tr>\n";
foreach($row1 as $value1) {
echo "<td>\n";
echo $value1;
echo "</td>\n";
}
echo "</tr>\n";
}
echo "</table>\n";

$querytwo = "SELECT column_one, column_two, column_five FROM tbltable WHERE column_five = 1989";
$results2 = mysql_query($querytwo) or die(mysql_error());
echo "Column One, Column Two, Column Five : </br>";
echo "<table border=\"1\">\n";
while ($row2 = mysql_fetch_assoc($results2)) {
echo "<tr>\n";
foreach($row2 as $value2) {
echo "<td>\n";
echo $value2;
echo "</td>\n";
}
echo "</tr>\n";
}
echo "</table>\n";

$querythree = "SELECT COUNT(column_five) FROM tbltable WHERE column_five = 1989";
$results3 = mysql_query($querythree) or die(mysql_error());
echo "Column 4 has this many 1989s : </br>";
echo "<table border=\"1\">\n";
while ($row3 = mysql_fetch_assoc($results3)) {
echo "<tr>\n";
foreach($row3 as $value3) {
echo "<td>\n";
echo $value3;
echo "</td>\n";
}
echo "</tr>\n";
}
echo "</table>\n";
?>  

Answer 1

$query = "SELECT column_one, column_two, column_four FROM tbltable;"

$results = mysql_query($query) or die(mysql_error());

$querytwo = "SELECT column_one, column_two, column_five FROM tbltable WHERE column_five = 1989";

$results = mysql_query($querytwo) or die(mysql_error());

$querythree = "SELECT COUNT(column_five) FROM tbltable WHERE column_five = 1989";

$results = mysql_query($querythree) or die(mysql_error());

您遇到的问题是使用相同的变量名覆盖了结果。

例：

$Var = "test";
 echo $Var; // Will output "test"
$Var = "Another String"; 
 echo $Var; // Will output "Another String" rather than "test"; 

因此附加：

$Results_a = ...;
$Results_b = ...;
$Results_c = ...;

因此，您可以轻松使用变量，您可以查看的另一件事是SQL连接： http : //dev.mysql.com/doc/refman/5.0/en/join.html减少了单独的查询量

Answer 2

您需要将查询保存到其他变量：

<?php
include("server_connect.php");

mysql_select_db("rnissen");

$query = "SELECT column_one, column_two, column_four FROM tbltable;"

$results1 = mysql_query($query) or die(mysql_error());

$querytwo = "SELECT column_one, column_two, column_five FROM tbltable WHERE column_five = 1989";

$results2 = mysql_query($querytwo) or die(mysql_error());

$querythree = "SELECT COUNT(column_five) FROM tbltable WHERE column_five = 1989";

$results3 = mysql_query($querythree) or die(mysql_error());

?>  

但是，这是使用mysqli_multi_query执行多个查询的更方便的方法：

来自文档的示例：

$query  = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";

/* execute multi query */
if (mysqli_multi_query($link, $query)) {
    do {
        /* store first result set */
        if ($result = mysqli_store_result($link)) {
            while ($row = mysqli_fetch_row($result)) {
                printf("%s\n", $row[0]);
            }
            mysqli_free_result($result);
        }
        /* print divider */
        if (mysqli_more_results($link)) {
            printf("-----------------\n");
        }
    } while (mysqli_next_result($link));
}

编辑：

对于更新的问题，您在这里缺少分号：

$query = "SELECT column_one, column_two, column_four FROM tbltable";