Rodbc Date Filter

I have been trying to set a query to a MS SQL database through RODBC. Unfortunately I cannot set appropriate date filters. I tried typing date in quotes and single quotes, DATE fun

Solution 1:

It is better to construct your sql query, using paste, specially when you deal with dates. here I convert the dates to numeric, but it is optionally( it depends with the data base, I think that MS SQL convert character to dates automatically). I create my query using paste and sep ='\n':

For example :

query <- paste(
  'SELECT ST03001, ST03003, ST03007, ST03015, ST03012, ST03020, ST03021, ST03022 ',
  'FROM ST031000',
  paste("WHERE ST03015 >" , as.numeric(as.Date('2013-05-01')),sep=''),
  sep='\n')

Then using cat:

cat(query)
SELECT ST03001, ST03003, ST03007, ST03015, ST03012, ST03020, ST03021, ST03022 
FROM ST031000
WHERE ST03015 >15826

You can also do this (no need to convert to a numeric)

query <- paste(
+   'SELECT ST03001, ST03003, ST03007, ST03015, ST03012, ST03020, ST03021, ST03022 ',
+   'FROM ST031000',
+   paste("WHERE ST03015 >'" , as.Date('2013-05-01'),"'",sep=''),
+   sep='\n')

> cat(query)
SELECT ST03001, ST03003, ST03007, ST03015, ST03012, ST03020, ST03021, ST03022 
FROM ST031000
WHERE ST03015 >'2013-05-01'

Here an example using sqldf package. I create some data:

values <- as.data.frame(matrix(sample(1:100,8*6*3,rep=T),ncol=8))
colnames(values) <- c('ST03001', 'ST03003', 'ST03007', 'ST03015', 'ST03012', 'ST03020', 'ST03021', 'ST03022') 
values$ST03015 = seq(as.Date("2012/1/1"), as.Date("2013/06/1"), length.out= nrow(values))

Then:

sqldf(query <- paste(
  'SELECT ST03001, ST03003, ST03007, ST03015, ST03012, ST03020, ST03021, ST03022 ',
  'FROM ST031000',
  paste("WHERE ST03015 >" , as.numeric(as.Date('2013-05-01')),sep=''),
  sep='\n'))

     ST03001ST03003ST03007ST03015ST03012ST03020ST03021ST0302217374582013-05-01828588582863712013-06-0137761544