title: Failed to connect the database when using sqldf in r
body: <p>I loaded a csv file to my R, and when I Tried to use sqldf to select some column, it always went to</p>
  
  <pre><code>Error in .local(drv, ...) : 
    Failed to connect to database: Error: Access denied for user 
    'User'@'localhost' (using password: NO)
  Error in !dbPreExists : invalid argument type
  </code></pre>
  
  <p>I don't know how to fix it.</p>
  
  <p>Here is my script:</p>
  
  <pre><code>library("RMySQL")
  library(sqldf)
  acs&lt;-read.csv("getdata_data_ss06pid.csv",head = T)
  sqldf("select pwgtp1 from acs where AGEP &lt; 50")
  </code></pre>