reorder it.

Author: gatorsmile

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala

@@ -380,15 +380,12 @@ object ColumnPruning extends Rule[LogicalPlan] {
         p
       }
 
-    // Eliminate the Projects with empty projectList
-    case p @ Project(projectList, child) if projectList.isEmpty => child
+    // Eliminate no-op Projects
+    case p @ Project(projectList, child) if sameOutput(child.output, p.output) => child
 
     // Can't prune the columns on LeafNode
     case p @ Project(_, l: LeafNode) => p
 
-    // Eliminate no-op Projects
-    case p @ Project(projectList, child) if sameOutput(child.output, p.output) => child
-
     // for all other logical plans that inherits the output from it's children
     case p @ Project(_, child) =>
       val required = child.references ++ p.references