parent(親) > child(子)の使い方

span1
span2
span3

  
$("#div1 > span").css("background-color", "#e7f7e7");
$("#div2 > span").css("background-color", "#e7f7e7");
$("#div3 > span").css("background-color", "#e7f7e7");  
          
<div id="div1">
  <span>span1</span>
</div>
<div id="div2">
  <div>
    <span>span2</span>
  </div>
</div>
<div id="div3"> 
  <div></div>
  <span>span3</span>    
</div>