在R中遍歷SQL

Question

我有一個sql代碼，想在上面放一個for循環

這是我對循環的誘惑，它不起作用：

list <- c(58362, 58384)
for (l in list){
"SELECT Top 3 G.MupolygonWktWgs84 as geom, l as mukey from SDA_Get_MupolygonWktWgs84_from_Mukey('462594') as G" }

這是使用sql的正確方法：

"SELECT Top 3 G.MupolygonWktWgs84 as geom, '58362' as mukey from SDA_Get_MupolygonWktWgs84_from_Mukey('462594') as G"

有人可以幫我弄清楚如何編寫此for循環嗎？

先感謝您！！！！

Answer 1

我試圖將數字轉換為字符串，並且有效：

list <- c(58362, 58384)
for (l in list) {
 q <- paste("SELECT G.MupolygonWktWgs84 as geom, '",l,"' as mukey from 
SDA_Get_MupolygonWktWgs84_from_Mukey('",l,"') as G",sep="")
}

Answer 2

您可以使用paste和適當的ODBC庫來完成此操作。 但是您需要使用各種設置來定義自己的con 。

list <- c(58362, 58384) result <- list() for (l in list){ result[l] <- dbGetQuery(con, paste("SELECT Top 3 G.MupolygonWktWgs84 as geom,", l, "as mukey from SDA_Get_MupolygonWktWgs84_from_Mukey('462594') as G")) }