I need to run multiple queries to get data from SQL server to R for multiple periods. I would like to use the period asa variable inside the query in sqlQuery function.
My query is the following:
fld_fec_car<-sqlQuery(dbNGC, "select fld_fec_car
from neptuno.data_mart.[dbo].[tbl_periodo_asig]
where fld_cod_emp='tg'
and fld_periodo ='072014'")
And I would like to have sth like
per='072014'
fld_fec_car<-sqlQuery(dbNGC, "select fld_fec_car
from neptuno.data_mart.[dbo].[tbl_periodo_asig]
where fld_cod_emp='tg'
and fld_periodo =&per")
Is it possible to include a variable value inside the sqlQuery function? Thanks.
There might be a more elegant solution, but what I usually do is make a function to generate the query text based on input:
genQuery <- function(arg)
{
lhs <- "select fld_fec_car
from neptuno.data_mart.[dbo].[tbl_periodo_asig]
where fld_cod_emp='tg'
and fld_periodo ='"
rhs <- "';"
##
Query <- paste0(lhs,arg,rhs)
Query <- gsub("\n"," ",Query)
Query <- gsub("\t"," ",Query)
return(Query)
}
##
> genQuery(123)
[1] "select fld_fec_car from neptuno.data_mart.[dbo].[tbl_periodo_asig] where fld_cod_emp='tg' and fld_periodo ='123';"
> genQuery(436)
[1] "select fld_fec_car from neptuno.data_mart.[dbo].[tbl_periodo_asig] where fld_cod_emp='tg' and fld_periodo ='436';"
The gsub("\\n"," ",...)
and gsub("\\t"," ",...)
are just to get get rid of the newline and tab characters - my SQL client doesn't accept them; yours might be different.
I Used paste:
a<-paste("SELECT fld_fec_car FROM neptuno.data_mart.[dbo].[tbl_periodo_asig] where fld_cod_emp='tg' and fld_periodo='", per, "'", sep='')
and then
sqlQuery(dbNGC, a)
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