Question

以下是代码段：

$check = mysql_query("SELECT occurrence_number FROM occurrence WHERE word_id = '$word_id' AND page_id = '$page_id'");

$array_row = mysql_fetch_array($check);
if($array_row['occurrence_number']){
   mysql_query("UPDATE occurrence SET occurrence_number = occurrence_number +1  WHERE word_id = '$word_id'"); 
   print "Updating";
}else{
   mysql_query("INSERT INTO occurrence (word_id,page_id) VALUES ($word_id,$page_id)");
   print "Indexing: $cur_word<br>";
}

我希望查询执行的操作：

如果在表occurrence中，存在word_id ='$word_id'和page_id = '$page_id'的行，则在向其添加1之后更新该行的occurrence_number列。

执行此查询时我得到的是：

代码永远不会输入if子句。每次执行代码时，都会生成一个新行，其中word_id，page_id，默认值occurrence_number（设置为0）和{{1} }（自动递增和主键）。

Answer 1

尝试 is_numeric （），如

if(is_numeric($array_row['occurrence_number'])){
     mysql_query("UPDATE occurrence SET occurrence_number = occurrence_number +1  WHERE word_id = '$word_id'"); 
     print "Updating";
}else{
     mysql_query("INSERT INTO occurrence (word_id,page_id) VALUES ($word_id,$page_id)");
     print "Indexing: $cur_word<br>";
}

或者您可以尝试

if($array_row['occurrence_number'] || $array_row['occurrence_number'] == '0'){

如果您尝试使用带有while循环的 mysql_fetch_array ，那么主要的是它将通过所有相关记录，否则它将只返回一条记录

while($array_row = mysql_fetch_array($check)) {
    //Put here the code...if else 
}

并且不使用mysql_ *函数，因为它们被删除。相反，您可以使用 mysqli _ *或 PDO 语句

Answer 2

这是因为MYSQL返回超过1行。尝试使用 mysql_fetch_row 而不是 mysql_fetch_array 。

或者就这样做：

while($my_fetch_var = mysql_fetch_array($check))
{ your if clause }

P.S。：还试着检查，你有多少行：

echo count($array_row);

Answer 3

我会检查row是否存在而不是检查实际值

$check = mysql_query("SELECT occurrence_number FROM occurrence WHERE word_id = '$word_id' AND page_id = '$page_id'");
if($array_row = mysql_fetch_array($check))
{
    mysql_query("UPDATE occurrence SET occurrence_number = occurrence_number +1  WHERE word_id = '$word_id'"); 
   print "Updating";
}else{
   mysql_query("INSERT INTO occurrence (word_id,page_id) VALUES ($word_id,$page_id)");
   print "Indexing: $cur_word<br>";
}

请注意，mysql_*函数已弃用，最好使用mysqli或PDO

Answer 4

if( $array_row['occurrence_number'] == '0' || $array_row['occurrence_number']  ){

while($array_row = mysql_fetch_array($check)) {

mysql_query("UPDATE occurrence SET occurrence_number = occurrence_number +1  WHERE     word_id = '$word_id'"); 
print "Updating";
}

为什么代码不进入`if`子句？

4 个答案: