[SPARK-15215][SQL] Fix Explain Parsing and Output

#### What changes were proposed in this pull request?
This PR is to address a few existing issues in `EXPLAIN`:
- The `EXPLAIN` options `LOGICAL | FORMATTED | EXTENDED | CODEGEN` should not be 0 or more match. It should 0 or one match. Parser does not allow users to use more than one option in a single command.
- The option `LOGICAL` is not supported. Issue an exception when users specify this option in the command.
- The output of `EXPLAIN ` contains a weird empty line when the output of analyzed plan is empty. We should remove it. For example:
  ```
  == Parsed Logical Plan ==
  CreateTable CatalogTable(`t`,CatalogTableType(MANAGED),CatalogStorageFormat(None,Some(org.apache.hadoop.mapred.TextInputFormat),Some(org.apache.hadoop.hive.ql.io.  HiveIgnoreKeyTextOutputFormat),None,false,Map()),List(CatalogColumn(col,int,true,None)),List(),List(),List(),-1,,1462725171656,-1,Map(),None,None,None), false

  == Analyzed Logical Plan ==

  CreateTable CatalogTable(`t`,CatalogTableType(MANAGED),CatalogStorageFormat(None,Some(org.apache.hadoop.mapred.TextInputFormat),Some(org.apache.hadoop.hive.ql.io.  HiveIgnoreKeyTextOutputFormat),None,false,Map()),List(CatalogColumn(col,int,true,None)),List(),List(),List(),-1,,1462725171656,-1,Map(),None,None,None), false

  == Optimized Logical Plan ==
  CreateTable CatalogTable(`t`,CatalogTableType(MANAGED),CatalogStorageFormat(None,Some(org.apache.hadoop.mapred.TextInputFormat),Some(org.apache.hadoop.hive.ql.io.  HiveIgnoreKeyTextOutputFormat),None,false,Map()),List(CatalogColumn(col,int,true,None)),List(),List(),List(),-1,,1462725171656,-1,Map(),None,None,None), false
  ...
  ```

#### How was this patch tested?
Added and modified a few test cases

Author: gatorsmile <gatorsmile@gmail.com>

Closes #12991 from gatorsmile/explainCreateTable.

1 files changed, 5 insertions, 15 deletions

diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveExplainSuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveExplainSuite.scala
index 542de724cc..17422ca1a0 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveExplainSuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveExplainSuite.scala
@@ -18,6 +18,7 @@
 package org.apache.spark.sql.hive.execution
 
 import org.apache.spark.sql.QueryTest
+import org.apache.spark.sql.catalyst.parser.ParseException
 import org.apache.spark.sql.hive.test.TestHiveSingleton
 import org.apache.spark.sql.test.SQLTestUtils
 
@@ -86,7 +87,7 @@ class HiveExplainSuite extends QueryTest with SQLTestUtils with TestHiveSingleto
            |CREATE TABLE t1
            |AS
            |SELECT * FROM jt
-      """.stripMargin).collect().map(_.mkString).mkString
+         """.stripMargin).collect().map(_.mkString).mkString
 
       val shouldContain =
         "== Parsed Logical Plan ==" :: "== Analyzed Logical Plan ==" :: "Subquery" ::
@@ -115,19 +116,8 @@ class HiveExplainSuite extends QueryTest with SQLTestUtils with TestHiveSingleto
       "== Physical Plan =="
     )
 
-    checkKeywordsExist(sql("EXPLAIN EXTENDED CODEGEN SELECT 1"),
-      "WholeStageCodegen",
-      "Generated code:",
-      "/* 001 */ public Object generate(Object[] references) {",
-      "/* 002 */   return new GeneratedIterator(references);",
-      "/* 003 */ }"
-    )
-
-    checkKeywordsNotExist(sql("EXPLAIN EXTENDED CODEGEN SELECT 1"),
-      "== Parsed Logical Plan ==",
-      "== Analyzed Logical Plan ==",
-      "== Optimized Logical Plan ==",
-      "== Physical Plan =="
-    )
+    intercept[ParseException] {
+      sql("EXPLAIN EXTENDED CODEGEN SELECT 1")
+    }
   }
 }