How to get sku list that hasn’t product images in magento?

Following is the SQL query by which you can get list of sku that hasn’t product images.

SELECT `sku` FROM `catalog_product_entity` AS pe LEFT JOIN `catalog_product_entity_varchar` AS pev ON pe.entity_id = pev.entity_id AND pev.attribute_id =74 WHERE pev.value = ''";

Image attribute id is 74 and it has not any value in catalog_product_entity_varchar value field against 74 attribute_id field.

You can also make this list as csv file by just write very simple code.

<?php
 header("Content-type:text/octect-stream");
 header("Content-Disposition:attachment;filename=no-image.csv");
  $conn = mysqli_connect("localhost","username","password","database"); // change this according to your database information
 $SQL = "SELECT `sku`
  FROM `catalog_product_entity` AS a
  LEFT JOIN `catalog_product_entity_varchar` AS b ON a.entity_id = b.entity_id
  AND b.attribute_id =74 WHERE b.value = ''";
 $R = mysqli_query($conn,$SQL); 
 echo "sku,image,small_image,thumbnail_image"."\n"; // print fields headings or names in csv file
 while($Rs = mysqli_fetch_assoc($R)){
   echo $Rs['sku'].",,,"."\n"; // print values in csv file
 }
 mysqli_free_result($R);
?>

In above code you will notice that I use 3 more fields other then sku it is because I will edit this csv file and write image name in image, small_image,thumbnail_image fileds and run profile from magento Data flow profiles to update products for images.