php中mysql查询结果为null时如何打印

Question

In MySQL query result is Null and how to display Null value in PHP. Below is the MySQL query

SELECT sum(qty),status,bs_id FROM booking_status where checkin <= '$date_search' and checkout='' and room_no='G 1'

I want to display message as no result found in PHP page

Answer 1

Thats not the best desciption, but if I understood you correctly, you have some query which returns an empty result. Basically you need to display a message which says "Booking not found" or anything like that.

$result = /*some mysql null result*/; if ($result === null) { return "Booking not found"; }

Answer 2

Something like this?

$query = mysql_query("SELECT * FROM table");

if(!$query)
{
    echo "Null";
}

Base on what you need

$query = mysql_query("SELECT sum(qty),status,bs_id FROM booking_status where checkin <= '$date_search' and checkout='' and room_no='G 1'");
if(!$query)
{
    echo "No results found.";
}
else
{
    // display the records here
}

Didn't try it. Don't know if it works.

Answer 3

There are two different possibilities you'll want to handle:

1. An error in the query, for whatever reason
2. An empty result set

Depending on which API you're using to build the query, it could look something like this:

$query = $mysqli->query("SELECT ....");
if(!$query){ // problem in query
  echo "Invalid query";
}
if($query->num_rows == 0){ // empty result set
  echo "No results found";
}else{
  // do something with results
}

Answer 4

Try following.

$query = "SELECT sum(qty),status,bs_id FROM booking_status where checkin <= '$date_search' and checkout='' and room_no='G 1'";
$result = mysql_query( $query );

if( count($result) <=0 ) {
   echo "No result found.";
}

Thanks

Answer 5

If you want a error free code then always do practice of handling errors in advance, whatever the result would be.

1. If you are writing any query then there will be chances of empty record or some other errors like(field not found, record is empty etc.)

2. What you have to do with this is always check for empty records like:

   $sql = "SELECT sum(qty),status,bs_id FROM booking_status where checkin <= '".$date_search."' and checkout='' and room_no='G 1'";
   $sql_result = mysql_query($sql);
   if(!$sql_result){
   echo "Sorry no records found";
   }else{
   $result = $sql_result->result_array();
   }
   

3. By using this way your error get automatically handle.

Answer 6

use mysql_num_rows it gives you 0 when you get no result (no rows) from query. You can print anything when it equals 0

$result = mysql_query("SELECT * FROM table1") or die(mysql_error());
$num_rows = mysql_num_rows($result);
if($num_rows == 0)
  echo "No Result Found";