Question

如果我从表单中获取数据，我可以使用以下代码检查重复项，但是当我导入csv文件时，如何检查重复项。

这里的select（=）只会对一个值有效，但如果有25行我会怎么做？

$check = mysql_query("SELECT * FROM table WHERE x= '$Thd'");

if ($x)
{
    if(mysql_num_rows($check) != 0)
    {
    header('location:nw.php?msg=cat exists');
    }
    else
    {

    )";

提前致谢。任何帮助表示赞赏。

Answer 1

你可以参考这个

Fgetcv

进入数组然后检查

Answer 2

mysql_query返回一个资源对象，可以通过迭代来获取每一行数据。请参阅the resource documentation中的示例，以获得良好的讨论。

Answer 3

好吧，你正在从CSV文件中提取数据。我通常使用fopen / fgets而不是PHP的finicky fgetcsv（），但无论如何，检查重复值所需要做的与上面的相似。如果我知道唯一的字段是什么，那么举一个例子会更容易，但是：

$check = mysql_query("SELECT `x` FROM `table` WHERE `x` = '$uniquecsvfield' LIMIT 1"); 
//LIMIT 1 will stop it from searching for more, since you only need to know if one result exists.
//If you don't do LIMIT 1 then it will go through the whole table even if it finds one.
//Can also do 'WHERE x = $uniquecsvfield1 AND y = $uniquecsvfield2, whatever, depending on how 
//many Fields need to be unique

if(mysql_num_rows($check) == 0)  //If no rows are returned
{
     mysql_query("INSERT INTO `table` VALUES blah blah blah"); //Insert
}
//Since you're gonna be processing the whole file, probably don't need to do anything if there is a 
//duplicate, it just won't insert it.  
//You could do an else that echo out "Duplicate found" or whatever

在PHP中导入CSV时检查重复项

3 个答案: