SELECT
    c.FederationID
   ,c.EmailAddress
   ,c.FirstName
   ,c.LastName
   ,c.event_link_click
FROM (
       SELECT
               yde.FederationID
              ,yde.EmailAddress
              ,yde.FirstName
              ,yde.LastName
              ,true as 'event_link_click'
       FROM yourDE yde
       INNER JOIN _click cl ON yde.EmailAddress = cl.SubscriberKey
       WHERE cl.LinkName = "yourLinkName"
) c

/* Target: yourDE */
/* Action: update */