在R中遍历SQL

Question

我有一个sql代码，想在上面放一个for循环

这是我对循环的诱惑，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" }

这是使用sql的正确方法：

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

有人可以帮我弄清楚如何编写此for循环吗？

先感谢您！！！！

Answer 1

我试图将数字转换为字符串，并且有效：

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和适当的ODBC库来完成此操作。 但是您需要使用各种设置来定义自己的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")) }