remove POWER part

Author: xinyunh

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala

@@ -126,8 +126,6 @@ class SqlParser extends StandardTokenParsers with PackratParsers {
   protected val SUBSTRING = Keyword("SUBSTRING")
   protected val SQRT = Keyword("SQRT")
   protected val ABS = Keyword("ABS")
-  protected val POW = Keyword("POW")
-  protected val POWER = Keyword("POWER")
 
   // Use reflection to find the reserved words defined in this class.
   protected val reservedWords =
@@ -332,9 +330,6 @@ class SqlParser extends StandardTokenParsers with PackratParsers {
     } |
     SQRT ~> "(" ~> expression <~ ")" ^^ { case exp => Sqrt(exp) } |
     ABS ~> "(" ~> expression <~ ")" ^^ { case exp => Abs(exp) } |
-    (POW | POWER) ~> "(" ~> expression ~ "," ~ expression <~ ")" ^^ {
-      case s ~ "," ~ p => Power(s,p)
-    } |
     ident ~ "(" ~ repsep(expression, ",") <~ ")" ^^ {
       case udfName ~ _ ~ exprs => UnresolvedFunction(udfName, exprs)
     }

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

@@ -144,40 +144,3 @@ case class Abs(child: Expression) extends UnaryExpression  {
 
   override def eval(input: Row): Any = n1(child, input, _.abs(_))
 }
-
-/**
- * A function that get the power value of two parameters.
- * First one is taken as base while second one taken as exponent
- */
-case class Power(base: Expression, exponent: Expression) extends Expression {
-  type EvaluatedType = Any
-
-  def dataType: DataType = {
-    if (!resolved) {
-      throw new UnresolvedException(this, s"Cannot resolve since $children are not resolved")
-    }
-    DoubleType
-  }
-  override def foldable = base.foldable && exponent.foldable
-  def nullable: Boolean = base.nullable || exponent.nullable
-  override def toString = s"Power($base, $exponent)"
-
-  override def children = base :: exponent :: Nil
-
-  override def eval(input: Row): Any = {
-    def convertToDouble(num: EvaluatedType): Double = {
-      num match {
-        case d:Double => d
-        case i:Integer => i.doubleValue()
-        case f:Float => f.toDouble
-      }
-    }
-
-    val base_v = base.eval(input)
-    val exponent_v = exponent.eval(input)
-
-    if ((base_v == null) || (exponent_v == null))  null
-    else pow(convertToDouble(base_v), convertToDouble(exponent_v))
-  }
-
-}

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -53,39 +53,6 @@ class SQLQuerySuite extends QueryTest with BeforeAndAfterAll {
       2.5)
   }
 
-  test("SPARK-3176 Added Parser of SQL POWER()") {
-    checkAnswer(
-      sql("SELECT POWER(0, 512.0)"),
-      0.0)
-    checkAnswer(
-      sql("SELECT POW(1.0, 256.0)"),
-      1.0)
-    checkAnswer(
-      sql("SELECT POWER(1, -128)"),
-      1.0)
-    checkAnswer(
-      sql("SELECT POW(-1.0, -63)"),
-      -1.0)
-    checkAnswer(
-      sql("SELECT POWER(-1, 32.0)"),
-      1.0)
-    checkAnswer(
-      sql("SELECT POW(2, 8)"),
-      256.0)
-    checkAnswer(
-      sql("SELECT POWER(0.5, 2)"),
-      0.25)
-    checkAnswer(
-      sql("SELECT POW(2, -2)"),
-      0.25)
-    checkAnswer(
-      sql("SELECT POWER(8, 1)"),
-      8.0)
-    checkAnswer(
-      sql("SELECT POW(16, 0.5)"),
-      4.0)
-  }
-
   test("SPARK-3176 Added Parser of SQL LAST()") {
     checkAnswer(
       sql("SELECT LAST(n) FROM lowerCaseData"),