仅从MYSQL数据库中检索1行数据

I am trying to input multiple pieces of data through a form and all the data will be separated by (,). I plan to use this data to find the corresponding id for further processing through an sql query.

Below is the code I use.

$key_code = explode(",", $keyword); 
 //$key_count = count($key_code);
 $list = "'". implode("','", $key_code) ."'";
 //$row_count = '';
 $sql4= "SELECT key_id FROM keyword WHERE key_code IN (".$list.")";
 if(!$result4 = mysql_query($sql4, $connect)) {
 mysql_close($connect);
 $error = true;
 }else{
  //$i = 0;
  while($row = mysql_fetch_array($result4)) {
  $keyword_id[] = $row['key_id'];
   //$i++;
   } 
   //return $keyword_id;   
  }

The problem i see is that keyword_id[0] is the only element that contains any data (the data is accurate). Even if I input multiple values through the aforementioned form.

I thought it might be an error in the sql but I echo'ed it and it looks like:

SELECT key_id FROM keyword WHERE key_code IN ('WED','WATER','WASTE')

The values in the brackets are exactly what I inputted.

I even tried to figure out how many rows are being returned by the query and it shows only 1. I assume something is wrong with my query but I cannot figure where.

Any help will be greatly appreciated.

Edit: Alright Solved the problem. Thanks to suggestions made I copied and pasted the $sql_query I had echo'ed on the website into mysql console; which resulted in only 1 row being retrieved. After taking a closer look I realized that there was a whitespace between ' and the second word. I believe the problem starts when I input the key_code as:

WED, WATER, WASTE

Instead inputting it as

WED,WATER,WASTE

fixes the problem. I think I should make it so that it works both ways though.

Anyway, thank you for the help.

I am pretty sure that the query is ok. How many rows do you get with just

SELECT key_id FROM keyword

I think that there is just one line that matches your WHERE.

Check the query directly in the database(with phpmyadmin, or in the mysql console), however this query seems to be working as you may assumed. If it returns only 1 row when you use it directly in the db, then maybe there is only one row in your table wich matches this query.