Add BigDecimal literal to parser.

Author: hvanhovell

sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4

@@ -633,6 +633,7 @@ number
     | MINUS? SMALLINT_LITERAL         #smallIntLiteral
     | MINUS? TINYINT_LITERAL          #tinyIntLiteral
     | MINUS? DOUBLE_LITERAL           #doubleLiteral
+    | MINUS? BIGDECIMAL_LITERAL       #bigDecimalLiteral
     ;
 
 nonReserved
@@ -928,6 +929,11 @@ DOUBLE_LITERAL
     (INTEGER_VALUE | DECIMAL_VALUE | SCIENTIFIC_DECIMAL_VALUE) 'D'
     ;
 
+BIGDECIMAL_LITERAL
+    :
+    (INTEGER_VALUE | DECIMAL_VALUE | SCIENTIFIC_DECIMAL_VALUE) 'BD'
+    ;
+
 IDENTIFIER
     : (LETTER | DIGIT | '_')+
     ;

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/literals.scala

@@ -266,7 +266,7 @@ case class Literal (value: Any, dataType: DataType) extends LeafExpression with
         case Double.NegativeInfinity => s"CAST('-Infinity' AS ${DoubleType.sql})"
         case _ => v + "D"
       }
-    case (v: Decimal, t: DecimalType) => s"CAST($v AS ${t.sql})"
+    case (v: Decimal, t: DecimalType) => v + "BD"
     case (v: Int, DateType) => s"DATE '${DateTimeUtils.toJavaDate(v)}'"
     case (v: Long, TimestampType) => s"TIMESTAMP('${DateTimeUtils.toJavaTimestamp(v)}')"
     case _ => value.toString

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala

@@ -26,7 +26,8 @@ import org.antlr.v4.runtime.{ParserRuleContext, Token}
 import org.antlr.v4.runtime.tree.{ParseTree, RuleNode, TerminalNode}
 
 import org.apache.spark.internal.Logging
-import org.apache.spark.sql.catalyst.{FunctionIdentifier, InternalRow, TableIdentifier}
+import org.apache.spark.sql.AnalysisException
+import org.apache.spark.sql.catalyst.{FunctionIdentifier, TableIdentifier}
 import org.apache.spark.sql.catalyst.analysis._
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.parser.SqlBaseParser._
@@ -1323,6 +1324,19 @@ class AstBuilder extends SqlBaseBaseVisitor[AnyRef] with Logging {
     numericLiteral(ctx, Double.MinValue, Double.MaxValue, DoubleType.simpleString)(_.toDouble)
   }
 
+  /**
+   * Create a BigDecimal Literal expression.
+   */
+  override def visitBigDecimalLiteral(ctx: BigDecimalLiteralContext): Literal = {
+    val raw = ctx.getText.substring(0, ctx.getText.length - 2)
+    try {
+      Literal(BigDecimal(raw).underlying())
+    } catch {
+      case e: AnalysisException =>
+        throw new ParseException(e.message, ctx)
+    }
+  }
+
   /**
    * Create a String literal expression.
    */

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/parser/ExpressionParserSuite.scala

@@ -392,6 +392,13 @@ class ExpressionParserSuite extends PlanTest {
     intercept("1.8E308D", s"does not fit in range")
     // TODO we need to figure out if we should throw an exception here!
     assertEqual("1E309", Literal(Double.PositiveInfinity))
+
+    // BigDecimal Literal
+    assertEqual("90912830918230182310293801923652346786BD",
+      Literal(BigDecimal("90912830918230182310293801923652346786").underlying()))
+    assertEqual("123.0E-28BD", Literal(BigDecimal("123.0E-28").underlying()))
+    assertEqual("123.08BD", Literal(BigDecimal("123.08").underlying()))
+    intercept("1.20E-38BD", "DecimalType can only support precision up to 38")
   }
 
   test("strings") {

sql/core/src/test/resources/sql-tests/inputs/literals.sql

@@ -27,6 +27,12 @@ select 9223372036854775807L, -9223372036854775808L;
 -- out of range long
 select 9223372036854775808L;
 
+-- big decimal parsing
+select 90912830918230182310293801923652346786BD, 123.0E-28BD, 123.08BD;
+
+-- out of range big decimal
+select 1.20E-38BD;
+
 -- integral parsing
 
 -- parse int