如果value为empty / null，则根据数据库的长度替换数据库中的值

Question

Scenario:

Database Table 
Column     Type      Length            Sample Values
emp_code   varchar     4            0011      0021    0012
emp_desc   varchar     2            01        03      01
emp_stat   varchar     1            1                 0

Problem:

I am querying so that I can write the result into a text file.

$file = "data.txt";
$f = fopen($file, "a");
$qry = "SELECT * FROM tbl_emp";
$result = mysqli_query($conn, $qry );
if(!$result) {
    echo "Cannot do query" . "<br/>";
exit;
}

$num_results =mysqli_num_rows($result);
for ($i=0; $i<=$num_results; $i++) {
    $row = mysqli_fetch_assoc ($result);
        $emp_code = (empty($row['emp_code']) ? "    " : $row['emp_code']); //replace with 4 spaces
        $emp_desc = (empty($row['emp_desc']) ? "  " : $row['emp_desc ']);  //replace with 2 spaces
        $emp_stat = (empty($row['emp_code']) ? " " : $row['emp_code']);  //replace with 1 space

     $data = "$emp_code $emp_desc $emp_stat
";
     fwrite($f,$data); 
}

Data.Txt should contain:

0011011
002103 
0012010

But this is the result:

0011011
002103 
001201

If the value of the row is 0, it replaces it with blank when it shouldn't. What needs to be changed to get the correct data? TIA.

Answer 1

Don't use empty. 0 is empty. Depending on what you are checking there it can be one of:

$emp_stat = (is_null($row[...]) ? " " : $row[...])
$emp_stat = (($row[...] === "") ? " " : $row[...])
$emp_stat = (is_numeric($row[...])? $row[...] : " ")

etc