Shiny:Reactive SQL queries (output of 1st query as input of 2nd query)

Question

is it possible to have 2 SQL queries, and take the output of 1st of them as an input of the 2nd?

What i meant, I would like use the first SQL query, maybe smthg like this?:

rs <- dbSendQuery(con, "Select distinct X From K.Tabelle order by X asc")
data <- fetch(rs)

Therefore i could get a list of uniqe values from column X. Further I would like to use this list as a choice in selectInput("select1",...) widget of shiny (and it would be great if i could as well have a choice to get all of the values), which will be further used in the second/final query:

query <- reactive( sprintf("select * from K.Tabelle",
                               " where", input$tablename, "=", input$select1, sep="")

Is it possible? I have no idea where i should put the first query? On the server side as well?

My code:

library(ROracle)
library(shiny)

get_data <- 
  function(query){
    on.exit(dbDisconnect(con)) ## important to close connection
    con <- dbConnect(dbDriver("Oracle"),"xx",username="user",password="pwd")
    dbGetQuery(con,query)
  }

server <- shinyServer(
  function(input, output) {

    query <-  reactive( sprintf("select * from K.Tabelle",
                               " where", input$tablename, "=", input$select1, sep="")
    ## simply  displaying reactive inputs
    output$table <- renderTable(
     get_data(query())
    )
  })

ui_panel <- 
  tabPanel("Test",
           sidebarLayout(
             sidebarPanel(
             ),
             mainPanel(
               tableOutput("table")
             )
           )
  )


ui <- shinyUI(navbarPage("Test",ui_panel))

runApp(list(ui=ui,server=server))

Thanks for the tipps