title: Error: could not find function "sqldf" using R to run SQL
body: <p>I faced a question,there is a error message to run <code>sqldf</code> package. I just load</p>
  
  <pre><code>install.packages("sqldf")
  install.packages("RSQLite")
  install.packages("tcltk2")
  library("sqldf")
  library("RSQLite")
  library("tcltk2")
  
  final &lt;-sqldf("select a.age,
                    a.height
             from a
             inner join b
             on
               a.id = b.id
             ")
  </code></pre>
  
  <blockquote>
    <p>Error: could not find function "sqldf"</p>
  </blockquote>
  
  <pre><code>sessionInfo()
  R version 3.2.0 (2015-04-16)
  Platform: x86_64-w64-mingw32/x64 (64-bit)
  Running under: Windows 7 x64 (build 7601) Service Pack 1
  
  locale:
  [1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
  [3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
  [5] LC_TIME=English_United States.1252    
  
  attached base packages:
  [1] tcltk     stats     graphics  grDevices utils     datasets  methods   base     
  
  other attached packages:
  [1] tcltk2_1.2-11
  
  loaded via a namespace (and not attached):
  [1] tools_3.2.0
  </code></pre>
  
  <p>Also, my R and Rstudio have latest version. I have Windows 7.</p>