如何在PHP中正确创建自定义函数？

Question

我创建了一个自定义函数,我收到此错误.我不认为我的脚本中存在"解析错误".

Parse error: syntax error, unexpected ',', expecting '&' or T_VARIABLE in C:\wamp\www\web template\test.php on line 8

---

<?php
require('global script/php/dbConnect.php');

$varName = 'sd';

echo checkDBDuplicate('account_list', 'memberID', $varName);

function checkDBDuplicate(tableName, dbFieldName, variableName) 
{
    $tableName = tableName;
    $dbFieldName = dbFieldName;
    $variableName = variableName;

    $searchDuplicate = mysql_query('
        SELECT $dbFieldName
        FROM $tableName
        WHERE $dbFieldName = $variableName
        ') or die(mysql_error());
    $countRow = mysql_num_rows($searchDuplicate);

    return $countRow;
}
?>

此脚本的目的是测试我是否可以在SELECT语句中使用变量.

Answer 1

变量应该有一个$前缀.所以

function checkDBDuplicate(tableName, dbFieldName, variableName) {

是错的,做到了

function checkDBDuplicate($tableName, $dbFieldName, $variableName) {

显然,进一步的情况也是如此,所以:

$tableName = tableName;
$dbFieldName = dbFieldName;
$variableName = variableName;

需要同样的待遇