PHP：如果输入值为空，则插入NULL

Question

i have been trying to insert NULL to my database if the value of input is empty but i still it insert empty and NULL string

Here's my code

this code returns blank

  if (empty($_POST['caller'])){ $caller= NULL; }else{ $caller =  mysqli_real_escape_string($con, $_POST['caller']);}

  or this

  $caller =  mysqli_real_escape_string($con, $_POST['caller']);
  $caller = !empty($caller_contact) ? "'$caller'" : NULL;

this code returns NULL string

  $caller =  mysqli_real_escape_string($con, $_POST['caller']);
  $caller = !empty($caller_contact) ? "'$caller'" : 'NULL';

 or this

  if (empty($_POST['caller'])){ $caller= 'NULL'; }else{ $caller =  mysqli_real_escape_string($con, $_POST['caller']);}

query

$sql_caller = "INSERT INTO `tblcall_info` VALUES ('','$save_inc_id','$call_time','$call_date','$caller','$caller_contact','$receiver','$device')";

i have also tried changing '$caller' to $caller but its an error.

can anyone help?. thanks

Answer 1

You can try this way:

remove single invated comma from query and set them to query it will surely work for you

if (empty($_POST['caller'])){ 
    $caller="NULL";
}else{ 
    $caller=mysqli_real_escape_string($con, $_POST['caller']);
    $caller="'$caller'";
}

$sql_caller = "INSERT INTO `tblcall_info` VALUES ('','$save_inc_id','$call_time','$call_date','$caller','$caller_contact','$receiver','$device')";

Answer 2

Try this method in the $sql_caller string:

INSERT INTO table_name (column1,column2,...)  VALUES(value1,value2,...);

And skip the column & it's value, which you want to be set as NULL.