[SPARK-4536][SQL] Add sqrt and abs to Spark SQL DSL

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/dsl/package.scala

@@ -147,6 +147,8 @@ package object dsl {
     def max(e: Expression) = Max(e)
     def upper(e: Expression) = Upper(e)
     def lower(e: Expression) = Lower(e)
+    def sqrt(e: Expression) = Sqrt(e)
+    def abs(e: Expression) = Abs(e)
 
     implicit class DslSymbol(sym: Symbol) extends ImplicitAttribute { def s = sym.name }
     // TODO more implicit class for literal?

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

@@ -19,7 +19,6 @@ package org.apache.spark.sql.catalyst.expressions
 
 import org.apache.spark.sql.catalyst.analysis.UnresolvedException
 import org.apache.spark.sql.catalyst.types._
-import scala.math.pow
 
 case class UnaryMinus(child: Expression) extends UnaryExpression {
   type EvaluatedType = Any

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

@@ -282,4 +282,72 @@ class DslQuerySuite extends QueryTest {
       (1, "1", "11") :: (2, "2", "22") :: (3, "3", "33") :: Nil
     )
   }
+
+  test("sqrt") {
+    checkAnswer(
+      testData.select(sqrt('key)).orderBy('key asc),
+      (1 to 100).map(n => Seq(math.sqrt(n)))
+    )
+
+    checkAnswer(
+      testData.select(sqrt('value), 'key).orderBy('key asc, 'value asc),
+      (1 to 100).map(n => Seq(math.sqrt(n), n))
+    )
+
+    checkAnswer(
+      testData.select(sqrt(Literal(null))),
+      (1 to 100).map(_ => Seq(null))
+    )
+  }
+
+  test("abs") {
+    checkAnswer(
+      testData.select(abs('key)).orderBy('key asc),
+      (1 to 100).map(n => Seq(n))
+    )
+
+    checkAnswer(
+      negativeData.select(abs('key)).orderBy('key desc),
+      (1 to 100).map(n => Seq(n))
+    )
+
+    checkAnswer(
+      testData.select(abs(Literal(null))),
+      (1 to 100).map(_ => Seq(null))
+    )
+  }
+
+  test("upper") {
+    checkAnswer(
+      lowerCaseData.select(upper('l)),
+      ('a' to 'd').map(c => Seq(c.toString.toUpperCase()))
+    )
+
+    checkAnswer(
+      testData.select(upper('value), 'key),
+      (1 to 100).map(n => Seq(n.toString, n))
+    )
+
+    checkAnswer(
+      testData.select(upper(Literal(null))),
+      (1 to 100).map(n => Seq(null))
+    )
+  }
+
+  test("lower") {
+    checkAnswer(
+      upperCaseData.select(lower('L)),
+      ('A' to 'F').map(c => Seq(c.toString.toLowerCase()))
+    )
+
+    checkAnswer(
+      testData.select(lower('value), 'key),
+      (1 to 100).map(n => Seq(n.toString, n))
+    )
+
+    checkAnswer(
+      testData.select(lower(Literal(null))),
+      (1 to 100).map(n => Seq(null))
+    )
+  }
 }

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

@@ -32,6 +32,10 @@ object TestData {
     (1 to 100).map(i => TestData(i, i.toString))).toSchemaRDD
   testData.registerTempTable("testData")
 
+  val negativeData = TestSQLContext.sparkContext.parallelize(
+    (1 to 100).map(i => TestData(-i, (-i).toString))).toSchemaRDD
+  negativeData.registerTempTable("negativeData")
+
   case class LargeAndSmallInts(a: Int, b: Int)
   val largeAndSmallInts =
     TestSQLContext.sparkContext.parallelize(