在R语句中使用R子句的where子句在SQL语句中使用它

Question

I have two tables; viz table1 = PID (primary key) + 20 other columns & 200 records from database1 AND table2 = [Serial no] (primary key) + 10 other columns & 300 records from database2.

I am trying to extract values from table2 where PID = [Serial no].

Note: PID = [SCK34ICV7, NSCK876DL, ......].

I refered "Pass string Variable in R script to use it in SQL statement"

t1 <- sqlquery(db1, "select * from table1")
r1 <- t1$PID
class(r1) = 'factor'
t2 <- sqlquery(db2, "select * from table2 where [Serial no] = '(",r1,")' ",sep ="")

I also tried other functions viz paste0(), fn$ from gsubfn and sprintf() and getting error like - 'c is not a recognized built in function name' ; 'Incorrect syntax'.

Please suggest the best way to do it.

Reg,

Mrutyunjaya

Answer 1

Your query is off. See here for what the proper format should be.

r1 <- c("PID1","PID2","PID3")

---

wrong

paste("select * from table2 where [Serial no] = '(",r1,")' ",sep ="")

output:

[1] "select * from table2 where [Serial no] = '(PID1)' " "select * from table2 where [Serial no] = '(PID2)' " "select * from table2 where [Serial no] = '(PID3)' "

---

correct

paste("select * from table2 where [Serial no] IN (",paste(r1,collapse=", "),") ",sep ="")

Output:

[1] "select * from table2 where [Serial no] IN (PID1, PID2, PID3) "

So the query becomes:

t2 <- sqlquery(db2,paste0("select * from table2 where [Serial no] IN (",paste(r1,collapse=", "),") ",sep =""))

Hope this helps.