sqlQuery <- function (query) {

  # creating DB connection object with RMysql package
  DB <- dbConnect(MySQL(), user='username', password='pass', dbname='databasename', host='localhost')

  # send Query to obtain result set

    rs <- dbSendQuery(DB, query)

  # get elements from result sets and convert to data frame
  result <- fetch(rs, -1)

  # to close resultset in RMySQL
  dbClearResult(dbListResults(DB)[[1]])

  # close db connection after function call exits
  on.exit(dbDisconnect(DB), add = FALSE)

  # return the dataframe
  return(result)
}

library(shiny)
library(shinydashboard)

ui <- dashboardPage(
  dashboardHeader(),
  dashboardSidebar(),
  dashboardBody(
   uiOutput("firstSelection")
  )
)
mydata <- sqlQuery("select name, address from table1")
server <- function(input, output) {

output$secondSelection <- renderUI({

selectInput("name", "Select Name", choices = mydata$name)

})
}

shinyApp(ui, server)