title: R dplyr distinct function cannot use .keep_all = TRUE
body: <p>I have an object testTable of the type below:
  [1] "tbl_Microsoft SQL Server" "tbl_dbi"                  "tbl_sql"                  "tbl_lazy"                 "tbl"
  When I want to de-dup the table based on one column but keep all the other columns, I use <code>testTable %&gt;% distinct(oneColumn, .keep_all = TRUE)</code>. But I always get the error below. I checked the internet and cannot find anyone else getting the same error. How can I achieve my goal? Thanks.</p>
  
  <p>Error: Can only find distinct value of specified columns if .keep_all is FALSE</p>
  
  <p>If I remove <code>.keep_all = TRUE</code>, the query works but only oneColumn is returned.</p>