R 查询动态哪里有闪亮的输入

Question

I query data from R shiny app

output$ceb_selector <- renderUI({
    selectInput("select_tab", label = ("ceb"),
                choices = list("xx" , "yy", "All"),
                selected = "All")

This is my old sql

    t1 <- dbGetQuery(pool,statement = paste0("select    ",input$date," , name ,
                          sum(",input$x1,"*y) as ",input$x1," ,
                          sum(gg) as ggsum
                          from table_name 
                          where name = '",input$name,"'
                          and ",input$date," between '",input$date_range[1],"' and '",input$date_range[2],"'
                          group by ",input$date," ,name ")  )  
write.table(t1, file="emp.csv", sep = ",", row.names=FALSE)

I want to add where condition from input$ceb that have 3 choices = xx, yy, all

But in database column ceb only have data xx and yy don't have all (I want use 'all' to select both xx and yy)

table

inputshiny

What I thought is If input = xx will where ceb = xx

If input = yy will where ceb = yy

If input = All will where xx and yy

I tried

paste0("select        ",input$date," , name ,
                      sum(",input$x1,"*y) as ",input$x1," ,
                      sum(gg) as ggsum
                      from table_name 
                      where name = '",input$name,"'
                      and ",input$date," between '",input$date_range[1],"' and '",input$date_range[2],"'
                      and ceb =
                      case 
                               when  ",input$ceb," = xx then 'xx'
                               when  ",input$ceb," = yy then 'yy' 
                      end 
                      group by ",input$date," ,name ")

AND

case 
   when  ",input$ceb," = xx then and tab = 'xx'
   when  ",input$ceb," = yy then and tab = 'yy' 
end 

It's still error.

Answer 1

I'm not going to be able to reproduce the full complexity of your table and shiny app, but here's a simplified local example where I think there are two methods.

I'm using sqldf on a local frame to mimic your postgres database; I don't think the specific DBMS matters in this case.

table_name <- data.frame(
  row = 1:4,
  ceb = c('xx', 'yy', 'xx', 'yy')
)

Query formed conditionally

input_ceb <- "xx"
qry <- "select * from table_name where row > 0"
qry2 <- if (input_ceb != "All") paste("and ceb = ", sQuote(input_ceb))
sqldf::sqldf(paste(qry, qry2))
#   row ceb
# 1   1  xx
# 2   3  xx

input_ceb <- "All"
qry <- "select * from table_name where row > 0"
qry2 <- if (input_ceb != "All") paste("and ceb = ", sQuote(input_ceb))
sqldf::sqldf(paste(qry, qry2))
#   row ceb
# 1   1  xx
# 2   2  yy
# 3   3  xx
# 4   4  yy

If you look at qry2 now, it's NULL , so the query will not contain the and ceb= component. (Note that you should make sure that the query before and after this conditionally-included portion can work equally with it present or absent.)

Query including more conditional

(Still using input_ceb as above.) This causes the DBMS to take into consideration if ceb is "All", short-circuiting the second half. I don't know that this is any better, but it works the same.

qry <- paste(
  "select * from table_name where row > 0 and ('All' = ", sQuote(input_ceb),
  "or ceb = ", sQuote(input_ceb), ")"
)
sqldf::sqldf(qry)

---

Bottom line, use whichever one makes more sense to you and/or incorporates well into the rest of your query generation.

Notes:

• I use sQuote here because I'm not using DBI , though like my comment on your question, you should consider being a little more defensive in your coding: use DBI::dbQuoteString in place of sQuote here. The DBMS may not like wrapping numbers in ticks, though, so use smartly.

• the only reason I included row > 0 was so that I had a where clause to which I could just add and ceb = '...' ; without row > 0 , there would be no where and therefore and would be a syntax violation. You won't need it, as I believe you have where clauses that are always present.

• you might find sprintf or glue::glue to be slightly better for interpolating strings in there; for instance, these are equivalent to the second example above:

   sprintf( "select * from table_name where row > 0 and ('All' = %s or ceb = %s)", sQuote(input_ceb), sQuote(input_ceb) ) glue::glue( "select * from table_name where row > 0 and ('All' = {sQuote(input_ceb)} or ceb = {sQuote(input_ceb)})" )