SQL query to AJAX not working, directly entered works fine

An SQL query gives no output through AJAX page when variables are passed in the query. Even the count of number of rows gives zero (0). An echo of the same query with the passed variables shows as having values.

When copy and pasting the same (replacing) from the browser page to the query in the AJAX page it gives a result.

The code is as follows (first SQL code in AJAX page with variables as parameter):

$qu="SELECT DISTINCT bk.bookname,bk.author,bk.publisher,bk.edition,bk.description,lam.article_name,bk.keywords,bk.qtyinstock FROM lib_article_master lam, lib_book_cd_master bk WHERE bk.bookname='$arr[2]' AND bk.author='$arr[3]' AND bk.publisher='$arr[4]' AND bk.article_id=lam.article_id";//here $arr[2],$arr[3],$arr[4] are variables from another query for comparison in AJAX page    
$r=QrySelect($qu);
echo " <br>  ".$qu;//query is echoed in browser
echo "<br>count : ".mysql_num_rows($r);//count of number of rows
$arr1=mysql_fetch_array($r);    
?>
    <table width="97%" border="0" >
      <tr 
        <td width="11%"><div align="left"><strong>Description </strong></div></td>
      </tr>       
    </table>
    <textarea name="txt_Keywords" style="width:90%; height:90px"><?php echo $arr1[4]; ?></textarea>

And the output is nothing.

The query, when taken from the browser and put back in code along with values for variables we are getting an output.

$qu="SELECT DISTINCT bk.bookname,bk.author,bk.publisher,bk.edition,bk.description,lam.article_name,bk.keywords,bk.qtyinstock FROM lib_article_master lam, lib_book_cd_master bk WHERE bk.bookname='Java Complete Reference' AND bk.author='Martin D Leuthen' AND bk.publisher='ABS Publications' AND bk.article_id=lam.article_id";//here $arr[2],$arr[3],$arr[4] are replaced as per browser output
$r=QrySelect($qu);
echo " <br>  ".$qu;//query is echoed in browser
echo "<br>count : ".mysql_num_rows($r);//count of number of rows
$arr1=mysql_fetch_array($r);    
?>
  开发者_开发技巧  <table width="97%" border="0" >
      <tr 
        <td width="11%"><div align="left"><strong>Description </strong></div></td>
      </tr>       
    </table>
    <textarea name="txt_Keywords" style="width:90%; height:90px"><?php echo $arr1[4]; ?></textarea>

We are getting an output for the above code with correct number of rows from the the database.

Any help will be great.

You should use string concatenation to build your query, like

"SELECT * FROM table WHERE param = '" . $value . "'"

So, your query should look like:

$qu="SELECT DISTINCT bk.bookname,bk.author,bk.publisher,bk.edition,bk.description,lam.article_name,bk.keywords,bk.qtyinstock FROM lib_article_master lam, lib_book_cd_master bk WHERE bk.bookname='".$arr[2]."' AND bk.author='".$arr[3]."' AND bk.publisher='".$arr[4]."' AND bk.article_id=lam.article_id";

Also, don't forget to escape string variables with mysql_real_escape_string().

Got it at last... PHEW... Just include 'TRIM()' and comparison problem got solved .Don't know still how it managed to work when code was pasted from browser but anyways its working. giving the code below ...

$fr0=trim($arr[0], "");//'TRIMS' ALL UNWANTED SPACES FOR COMPARISON TO BE PERFECT
$fr1=trim($arr[1], "");
$fr2=trim($arr[2], "");
$fr3=trim($arr[3], "");
$bkr0=strtolower($fr0);//HERE EVERY SINGLE CHARCTER IS TURNED TO 'LOWER CASE' TO REMOVE ALL POSSIBLE WAYS OF ERRORS IN COMPARISON
$bkr1=strtolower($fr1);
$bkr2=strtolower($fr2);
$bkr3=strtolower($fr3);
//NOW COMPARISON FOR EACH VALUE IS DONE IN A WHILE LOOP BY 'mysql_fetch_row'

thank u all for your effort... it really meant a lot !