title: Excel data validation conditional on another cell value
body: <p>Here's the context:</p>
  
  <pre><code>Sheet 1 : 
  A1 = "50255"
  A2 = "Soccer players"
  A3 = The cell I'm having a problem with
  
  Sheet 2 :
  A1:A5 : List of soccer plays (Ronaldo, Zidane...)
  
  Sheet 3 :
  A lot of datas in which I can possibly find my Sheet1!A1 value
  </code></pre>
  
  <p>I'd like to be able to do this :</p>
  
  <pre><code>If A1&lt;&gt;"" then Vlookup in Sheet 3 and print my value "50255".
  If A1="" then diplay the list of possible values you can set for Sheet2!Soccer players (Ronaldo, Zidane...)
  </code></pre>
  
  <p>Problem : I'm able to do both things in 2 differents cells but I cannot manage to do what I want in one cell...</p>
  
  <p>To sum up : I'd like to have either the result of my <code>Vlookup</code> or (if empty) a list of possible values.</p>
  
  <p>What I've tried in data validation:</p>
  
  <pre><code>=SI($E$31&lt;&gt;"";RECHERCHEV($E$31;'1 - Data players'!$G:$XFD;EQUIV('2 - OD'!$E38;'1 - Data players'!$G$6:$EX$6;0);FAUX);indirect($E$38))
  </code></pre>
  
  <p>Formula in English Excel:</p>
  
  <pre><code>=IF($E$31&lt;&gt;"",VLOOKUP($E$31,'1 - Data players'!$G:$XFD,MATCH('2 - OD'!$E38,'1 - Data players'!$G$6:$EX$6,0),FALSE),INDIRECT($E$38))
  </code></pre>
  
  <p>Could you help me? </p>