[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.

3 files changed, 38 insertions, 28 deletions

diff --git a/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala
index aec450e0a6..013a90875e 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala
@@ -212,7 +212,7 @@ class MathExpressionsSuite extends QueryTest with SharedSQLContext {
       Seq(Row(5, 10, 0), Row(55, 60, 100), Row(555, 560, 600))
     )
 
-    val pi = "3.1415BD"
+    val pi = "3.1415"
     checkAnswer(
       sql(s"SELECT round($pi, -3), round($pi, -2), round($pi, -1), " +
         s"round($pi, 0), round($pi, 1), round($pi, 2), round($pi, 3)"),
@@ -367,6 +367,16 @@ class MathExpressionsSuite extends QueryTest with SharedSQLContext {
     checkAnswer(
       input.toDF("key", "value").selectExpr("abs(key) a").sort("a"),
       input.map(pair => Row(pair._2)))
+
+    checkAnswer(
+      sql("select abs(0), abs(-1), abs(123), abs(-9223372036854775807), abs(9223372036854775807)"),
+      Row(0, 1, 123, 9223372036854775807L, 9223372036854775807L)
+    )
+
+    checkAnswer(
+      sql("select abs(0.0), abs(-3.14159265), abs(3.14159265)"),
+      Row(BigDecimal("0.0"), BigDecimal("3.14159265"), BigDecimal("3.14159265"))
+    )
   }
 
   test("log2") {
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
index b159346bed..47308966e9 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
@@ -1174,19 +1174,19 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
 
   test("Floating point number format") {
     checkAnswer(
-      sql("SELECT 0.3"), Row(0.3)
+      sql("SELECT 0.3"), Row(BigDecimal(0.3))
     )
 
     checkAnswer(
-      sql("SELECT -0.8"), Row(-0.8)
+      sql("SELECT -0.8"), Row(BigDecimal(-0.8))
     )
 
     checkAnswer(
-      sql("SELECT .5"), Row(0.5)
+      sql("SELECT .5"), Row(BigDecimal(0.5))
     )
 
     checkAnswer(
-      sql("SELECT -.18"), Row(-0.18)
+      sql("SELECT -.18"), Row(BigDecimal(-0.18))
     )
   }
 
@@ -1200,11 +1200,11 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
     )
 
     checkAnswer(
-      sql("SELECT 9223372036854775808BD"), Row(new java.math.BigDecimal("9223372036854775808"))
+      sql("SELECT 9223372036854775808"), Row(new java.math.BigDecimal("9223372036854775808"))
     )
 
     checkAnswer(
-      sql("SELECT -9223372036854775809BD"), Row(new java.math.BigDecimal("-9223372036854775809"))
+      sql("SELECT -9223372036854775809"), Row(new java.math.BigDecimal("-9223372036854775809"))
     )
   }
 
@@ -1219,11 +1219,11 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
     )
 
     checkAnswer(
-      sql("SELECT -5.2BD"), Row(BigDecimal(-5.2))
+      sql("SELECT -5.2"), Row(BigDecimal(-5.2))
     )
 
     checkAnswer(
-      sql("SELECT +6.8"), Row(6.8d)
+      sql("SELECT +6.8e0"), Row(6.8d)
     )
 
     checkAnswer(
@@ -1598,20 +1598,20 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
   }
 
   test("decimal precision with multiply/division") {
-    checkAnswer(sql("select 10.3BD * 3.0BD"), Row(BigDecimal("30.90")))
-    checkAnswer(sql("select 10.3000BD * 3.0BD"), Row(BigDecimal("30.90000")))
-    checkAnswer(sql("select 10.30000BD * 30.0BD"), Row(BigDecimal("309.000000")))
-    checkAnswer(sql("select 10.300000000000000000BD * 3.000000000000000000BD"),
+    checkAnswer(sql("select 10.3 * 3.0"), Row(BigDecimal("30.90")))
+    checkAnswer(sql("select 10.3000 * 3.0"), Row(BigDecimal("30.90000")))
+    checkAnswer(sql("select 10.30000 * 30.0"), Row(BigDecimal("309.000000")))
+    checkAnswer(sql("select 10.300000000000000000 * 3.000000000000000000"),
       Row(BigDecimal("30.900000000000000000000000000000000000", new MathContext(38))))
-    checkAnswer(sql("select 10.300000000000000000BD * 3.0000000000000000000BD"),
+    checkAnswer(sql("select 10.300000000000000000 * 3.0000000000000000000"),
       Row(null))
 
-    checkAnswer(sql("select 10.3BD / 3.0BD"), Row(BigDecimal("3.433333")))
-    checkAnswer(sql("select 10.3000BD / 3.0BD"), Row(BigDecimal("3.4333333")))
-    checkAnswer(sql("select 10.30000BD / 30.0BD"), Row(BigDecimal("0.343333333")))
-    checkAnswer(sql("select 10.300000000000000000BD / 3.00000000000000000BD"),
+    checkAnswer(sql("select 10.3 / 3.0"), Row(BigDecimal("3.433333")))
+    checkAnswer(sql("select 10.3000 / 3.0"), Row(BigDecimal("3.4333333")))
+    checkAnswer(sql("select 10.30000 / 30.0"), Row(BigDecimal("0.343333333")))
+    checkAnswer(sql("select 10.300000000000000000 / 3.00000000000000000"),
       Row(BigDecimal("3.433333333333333333333333333", new MathContext(38))))
-    checkAnswer(sql("select 10.3000000000000000000BD / 3.00000000000000000BD"),
+    checkAnswer(sql("select 10.3000000000000000000 / 3.00000000000000000"),
       Row(BigDecimal("3.4333333333333333333333333333", new MathContext(38))))
   }
 
@@ -1637,13 +1637,13 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
   }
 
   test("precision smaller than scale") {
-    checkAnswer(sql("select 10.00BD"), Row(BigDecimal("10.00")))
-    checkAnswer(sql("select 1.00BD"), Row(BigDecimal("1.00")))
-    checkAnswer(sql("select 0.10BD"), Row(BigDecimal("0.10")))
-    checkAnswer(sql("select 0.01BD"), Row(BigDecimal("0.01")))
-    checkAnswer(sql("select 0.001BD"), Row(BigDecimal("0.001")))
-    checkAnswer(sql("select -0.01BD"), Row(BigDecimal("-0.01")))
-    checkAnswer(sql("select -0.001BD"), Row(BigDecimal("-0.001")))
+    checkAnswer(sql("select 10.00"), Row(BigDecimal("10.00")))
+    checkAnswer(sql("select 1.00"), Row(BigDecimal("1.00")))
+    checkAnswer(sql("select 0.10"), Row(BigDecimal("0.10")))
+    checkAnswer(sql("select 0.01"), Row(BigDecimal("0.01")))
+    checkAnswer(sql("select 0.001"), Row(BigDecimal("0.001")))
+    checkAnswer(sql("select -0.01"), Row(BigDecimal("-0.01")))
+    checkAnswer(sql("select -0.001"), Row(BigDecimal("-0.001")))
   }
 
   test("external sorting updates peak execution memory") {
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala
index 8de8ba355e..a3c6a1d7b2 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/json/JsonSuite.scala
@@ -442,13 +442,13 @@ class JsonSuite extends QueryTest with SharedSQLContext with TestJsonData {
 
     // Number and String conflict: resolve the type as number in this query.
     checkAnswer(
-      sql("select num_str + 1.2BD from jsonTable where num_str > 14"),
+      sql("select num_str + 1.2 from jsonTable where num_str > 14"),
       Row(BigDecimal("92233720368547758071.2"))
     )
 
     // Number and String conflict: resolve the type as number in this query.
     checkAnswer(
-      sql("select num_str + 1.2BD from jsonTable where num_str >= 92233720368547758060BD"),
+      sql("select num_str + 1.2 from jsonTable where num_str >= 92233720368547758060"),
       Row(new java.math.BigDecimal("92233720368547758071.2"))
     )