mysql - 将多个选择从 selectizeInput 传递到 MySQL 查询

Question

我正在尝试将 selectizeInput 的多个值传递给 MySQL 查询。

问题是在 Shiny 的应用程序中这种操作的正确语法是什么？

我尝试过并且正在使用一个值

  library(shiny)
  library(DBI)
  library(RMySQL)

  server <- shinyServer(function(input, output, session) {
            con <- dbConnect(MySQL(), user='user', port = 3306, 
   password='pwd', dbname='db', host='host' )

           on.exit(dbDisconnect(con), add = TRUE) 

  output$textview <- renderUI({

         con <- dbConnect(MySQL(), user='user', port = 3306, password='pwd', 
               dbname='db', host='host' )

         on.exit(dbDisconnect(con), add = TRUE)


       text <- reactive({
                dbGetQuery(con, statement = 
                paste0(" SELECT author,  title, publicationDate,  FROM publications  
               WHERE publications.year LIKE %'",input$year,"'% ")
             )
               })

                text <-text()
                HTML(text)

          })




   session$onSessionEnded(function() { dbDisconnect(con) })
     })


 ui_panel <- 
      tabPanel("Multi-Select Input Test",
        sidebarLayout(
           sidebarPanel( 


         selectizeInput('year', 'Select Year of publication:', choices = 
         publications.year, multiple = TRUE  options = list(maxOptions = 5)
         ),

                   br(),
                   submitButton("Update Text View"),
                   br()
       ),
       mainPanel(
       tabsetPanel(tabPanel("Text",htmlOutput("textview"))

       )
     )
))


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

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

MySQL 命令中允许我从 selectizeInput (input$year) 传递多个值的正确语法是什么？我尝试使用 IN 而不是 LIKE，如下所示，但它不起作用

    text <- reactive({
                dbGetQuery(con, statement = 
                paste0(" SELECT author,  title, publicationDate,  FROM 
                publications WHERE publications.year IN %'",input$year,"'% ")
             )
               })

Answer 1

您需要构造一个与此类似的 SQL:

SELECT * FROM publications WHERE year IN (2016, 2017)

这应该生成:

text <- reactive({
  year_selected <- paste(input$year, collapse = ',')
  sql = paste("SELECT * FROM publications WHERE year IN (",year_selected,")")
  dbGetQuery(con, statement = sql)
})

一个最小的 Shiny 应用程序:

library(shiny)
ui <- fluidPage(
   sidebarLayout(
      sidebarPanel(
        selectizeInput('year', 'Select Year of publication:',
                       choices = c(2017L, 2018L),
                       multiple = TRUE,
                       options = list(maxOptions = 5)
        )
      ),
      mainPanel(
        verbatimTextOutput('text')
      )
   )
)

server <- function(input, output) {
   output$text <- renderText({
     library(glue)
     year_selected <- paste(input$year, collapse = ',')
     glue("SELECT * FROM publications WHERE year IN ({year_selected})")
   })
}

shinyApp(ui = ui, server = server)