[SPARK-12848][SQL] Change parsed decimal literal datatype from Double to Decimal

The current parser turns a decimal literal, for example ```12.1```, into a Double. The problem with this approach is that we convert an exact literal into a non-exact ```Double```. The PR changes this behavior, a Decimal literal is now converted into an extact ```BigDecimal```.

The behavior for scientific decimals, for example ```12.1e01```, is unchanged. This will be converted into a Double.

This PR replaces the ```BigDecimal``` literal by a ```Double``` literal, because the ```BigDecimal``` is the default now. You can use the double literal by appending a 'D' to the value, for instance: ```3.141527D```

cc davies rxin

Author: Herman van Hovell <hvanhovell@questtec.nl>

Closes #10796 from hvanhovell/SPARK-12848.

1 files changed, 1 insertions, 1 deletions

diff --git a/R/pkg/inst/tests/testthat/test_sparkSQL.R b/R/pkg/inst/tests/testthat/test_sparkSQL.R
index 14d40d5066..a389dd71a2 100644
--- a/R/pkg/inst/tests/testthat/test_sparkSQL.R
+++ b/R/pkg/inst/tests/testthat/test_sparkSQL.R
@@ -1812,7 +1812,7 @@ test_that("Method coltypes() to get and set R's data types of a DataFrame", {
   expect_equal(coltypes(x), "map<string,string>")
 
   df <- selectExpr(read.json(sqlContext, jsonPath), "name", "(age * 1.21) as age")
-  expect_equal(dtypes(df), list(c("name", "string"), c("age", "double")))
+  expect_equal(dtypes(df), list(c("name", "string"), c("age", "decimal(24,2)")))
 
   df1 <- select(df, cast(df$age, "integer"))
   coltypes(df) <- c("character", "integer")