[SPARK-16828][SQL] remove MaxOf and MinOf

## What changes were proposed in this pull request?

These 2 expressions are not needed anymore after we have `Greatest` and `Least`. This PR removes them and related tests.

## How was this patch tested?

N/A

Author: Wenchen Fan <wenchen@databricks.com>

Closes #14434 from cloud-fan/minor1.

2 files changed, 0 insertions, 114 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala
index 7ff8795d4f..77d40a5079 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala
@@ -361,116 +361,6 @@ case class Remainder(left: Expression, right: Expression)
   }
 }
 
-case class MaxOf(left: Expression, right: Expression)
-  extends BinaryArithmetic with NonSQLExpression {
-
-  // TODO: Remove MaxOf and MinOf, and replace its usage with Greatest and Least.
-
-  override def inputType: AbstractDataType = TypeCollection.Ordered
-
-  override def nullable: Boolean = left.nullable && right.nullable
-
-  private lazy val ordering = TypeUtils.getInterpretedOrdering(dataType)
-
-  override def eval(input: InternalRow): Any = {
-    val input1 = left.eval(input)
-    val input2 = right.eval(input)
-    if (input1 == null) {
-      input2
-    } else if (input2 == null) {
-      input1
-    } else {
-      if (ordering.compare(input1, input2) < 0) {
-        input2
-      } else {
-        input1
-      }
-    }
-  }
-
-  override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
-    val eval1 = left.genCode(ctx)
-    val eval2 = right.genCode(ctx)
-    val compCode = ctx.genComp(dataType, eval1.value, eval2.value)
-
-    ev.copy(code = eval1.code + eval2.code + s"""
-      boolean ${ev.isNull} = false;
-      ${ctx.javaType(left.dataType)} ${ev.value} =
-        ${ctx.defaultValue(left.dataType)};
-
-      if (${eval1.isNull}) {
-        ${ev.isNull} = ${eval2.isNull};
-        ${ev.value} = ${eval2.value};
-      } else if (${eval2.isNull}) {
-        ${ev.isNull} = ${eval1.isNull};
-        ${ev.value} = ${eval1.value};
-      } else {
-        if ($compCode > 0) {
-          ${ev.value} = ${eval1.value};
-        } else {
-          ${ev.value} = ${eval2.value};
-        }
-      }""")
-  }
-
-  override def symbol: String = "max"
-}
-
-case class MinOf(left: Expression, right: Expression)
-  extends BinaryArithmetic with NonSQLExpression {
-
-  // TODO: Remove MaxOf and MinOf, and replace its usage with Greatest and Least.
-
-  override def inputType: AbstractDataType = TypeCollection.Ordered
-
-  override def nullable: Boolean = left.nullable && right.nullable
-
-  private lazy val ordering = TypeUtils.getInterpretedOrdering(dataType)
-
-  override def eval(input: InternalRow): Any = {
-    val input1 = left.eval(input)
-    val input2 = right.eval(input)
-    if (input1 == null) {
-      input2
-    } else if (input2 == null) {
-      input1
-    } else {
-      if (ordering.compare(input1, input2) < 0) {
-        input1
-      } else {
-        input2
-      }
-    }
-  }
-
-  override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
-    val eval1 = left.genCode(ctx)
-    val eval2 = right.genCode(ctx)
-    val compCode = ctx.genComp(dataType, eval1.value, eval2.value)
-
-    ev.copy(code = eval1.code + eval2.code + s"""
-      boolean ${ev.isNull} = false;
-      ${ctx.javaType(left.dataType)} ${ev.value} =
-        ${ctx.defaultValue(left.dataType)};
-
-      if (${eval1.isNull}) {
-        ${ev.isNull} = ${eval2.isNull};
-        ${ev.value} = ${eval2.value};
-      } else if (${eval2.isNull}) {
-        ${ev.isNull} = ${eval1.isNull};
-        ${ev.value} = ${eval1.value};
-      } else {
-        if ($compCode < 0) {
-          ${ev.value} = ${eval1.value};
-        } else {
-          ${ev.value} = ${eval2.value};
-        }
-      }""")
-  }
-
-  override def symbol: String = "min"
-}
-
 @ExpressionDescription(
   usage = "_FUNC_(a, b) - Returns the positive modulo",
   extended = "> SELECT _FUNC_(10,3);\n 1")
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
index fe328fd598..75130007b9 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
@@ -662,10 +662,6 @@ object NullPropagation extends Rule[LogicalPlan] {
       case e @ Substring(_, Literal(null, _), _) => Literal.create(null, e.dataType)
       case e @ Substring(_, _, Literal(null, _)) => Literal.create(null, e.dataType)
 
-      // MaxOf and MinOf can't do null propagation
-      case e: MaxOf => e
-      case e: MinOf => e
-
       // Put exceptional cases above if any
       case e @ BinaryArithmetic(Literal(null, _), _) => Literal.create(null, e.dataType)
       case e @ BinaryArithmetic(_, Literal(null, _)) => Literal.create(null, e.dataType)