PHP for循环变量未分配

Question

I have a for loop that writes the results of a query into a table. I have a variable ($rID_s) that is being assigned from a value in the query. For some reason, it omits the first iteration. I have a variable for the total rows of the query and it is assigning the correct number. I've tried setting $i = 0 and $i = 1 and it still omits the first iteration of the array. If $i is set to 0, it adds a null record to the table.

See below, the value for $rID_s is the variable that is not being assigned on the first iteration of the loop. Thanks in advance:

for ($i=1; $i <= $totalRows_rsClassReg; $i++) {

        $row = mysql_fetch_array($rsClassReg);
        $rID_s = $row['class_registry_student_ID_fk'];

        mysql_select_db($database_SCOPE_test, $SCOPE_test);
        $sql_aInstance = sprintf("INSERT INTO assignment_registry (assignment_reg_assignment_ID_fk, assignment_reg_student_ID_fk) VALUES (%s, %s)",
                    GetSQLValueString($aID, "int"),
                    GetSQLValueString($rID_s, "int"));
        $Insert_aInstance = mysql_query($sql_aInstance, $SCOPE_test) or die(mysql_error());
        echo $row['class_registry_student_ID_fk'] . " - ";
        echo "Instanced";
        echo "</br>";
    }

Answer 1

You did not provide enough information to answer your question, so I'm going to totally left field you and provide another way of doing this that should make your question obsolete.

There are a lot of things you could and should be doing differently here. Imagine that your queries to your database are a bus and each query is a bus trip. It is better to fill up your bus with more data, then to take multiple bus trips.

// do this up here
mysql_select_db($database_SCOPE_test, $SCOPE_test);

if( ! empty( $oneDimensionalArrayOfIds ) ){
    $query = " SELECT `col` FROM `table` WHERE ( ". implode( 'AND', $oneDimensionalArrayOfIds ) ." ) ";  // the 1-D array is getting your r_IDs or whatever
    $rsClassReg = sqlarr( $query );
    if( ! empty( $rsClassReg ) ){
        $sqlInserts = NULL;
        foreach( $rsClassReg as $r ){
            $sqlInserts[] =  sprintf("INSERT INTO assignment_registry (assignment_reg_assignment_ID_fk, assignment_reg_student_ID_fk) VALUES (%s, %s)", GetSQLValueString($aID, "int"),  GetSQLValueString($rID_s, "int"));  
            // not sure where you are getting AIDs from (africa?  har har)...
        }
        if( ! empty( $sqlInserts ) ){
            sqlquery( implode( "; ", $sqlInserts ) );
        }
    }
}

Here's a freebie - A long time ago, I used to use these functions. Now a days, I use a custom query maker and PDO and save myself a lot of work. Here you go...

function sqlarr($sql, $numass=MYSQL_BOTH) {
    // MYSQL_NUM  MYSQL_ASSOC  MYSQL_BOTH
    $got = array();
    $result=mysql_query($sql) or die("$sql: " . mysql_error());                             

    if(mysql_num_rows($result) == 0)
        return $got;
    mysql_data_seek($result, 0);
    while ($row = mysql_fetch_array($result, $numass)) {
        array_push($got, $row);
    }
    return $got;
} 

// Sql fetch assoc
function sqlassoc($sql){
    $query = mysql_query($sql) or die("$sql:". mysql_error());
    $row = mysql_fetch_assoc($query);
    return $row;
}

function sqlrow($sql){
    $query = mysql_query($sql) or die("$sql:". mysql_error());
    $row = mysql_fetch_row($query);
    return $row;
}

function sqlquery($sql){
    $query = mysql_query($sql) or die("$sql:". mysql_error());
    return $row;
}