[SPARK-14518][SQL] Support Comment in CREATE VIEW

#### What changes were proposed in this pull request?
**HQL Syntax**: [Create View](https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-Create/Drop/AlterView
)
```SQL
CREATE VIEW [IF NOT EXISTS] [db_name.]view_name [(column_name [COMMENT column_comment], ...) ]
  [COMMENT view_comment]
  [TBLPROPERTIES (property_name = property_value, ...)]
  AS SELECT ...;
```
Add a support for the `[COMMENT view_comment]` clause

#### How was this patch tested?
Modified the existing test cases to verify the correctness.

Author: gatorsmile <gatorsmile@gmail.com>
Author: xiaoli <lixiao1983@gmail.com>
Author: Xiao Li <xiaoli@Xiaos-MacBook-Pro.local>

Closes #12288 from gatorsmile/addCommentInCreateView.

sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/HiveSqlParser.scala

@@ -26,18 +26,13 @@ import org.apache.hadoop.hive.ql.session.SessionState
 import org.apache.hadoop.hive.serde.serdeConstants
 import org.apache.hadoop.hive.serde2.`lazy`.LazySimpleSerDe
 
-import org.apache.spark.sql.AnalysisException
-import org.apache.spark.sql.catalyst.analysis.UnresolvedGenerator
 import org.apache.spark.sql.catalyst.catalog._
-import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.parser._
 import org.apache.spark.sql.catalyst.parser.SqlBaseParser._
 import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan
 import org.apache.spark.sql.execution.SparkSqlAstBuilder
 import org.apache.spark.sql.execution.command.CreateTable
-import org.apache.spark.sql.hive.{CreateTableAsSelect => CTAS, CreateViewAsSelect => CreateView}
-import org.apache.spark.sql.hive.{HiveGenericUDTF, HiveMetastoreTypes, HiveSerDe}
-import org.apache.spark.sql.hive.HiveShim.HiveFunctionWrapper
+import org.apache.spark.sql.hive.{CreateTableAsSelect => CTAS, CreateViewAsSelect => CreateView, HiveSerDe}
 
 /**
  * Concrete parser for HiveQl statements.
@@ -252,9 +247,6 @@ class HiveSqlAstBuilder extends SparkSqlAstBuilder {
     if (ctx.identifierList != null) {
       throw new ParseException(s"Operation not allowed: partitioned views", ctx)
     } else {
-      if (ctx.STRING != null) {
-        throw new ParseException("Unsupported operation: COMMENT clause", ctx)
-      }
       val identifiers = Option(ctx.identifierCommentList).toSeq.flatMap(_.identifierComment.asScala)
       val schema = identifiers.map { ic =>
         CatalogColumn(ic.identifier.getText, null, nullable = true, Option(ic.STRING).map(string))
@@ -262,6 +254,7 @@ class HiveSqlAstBuilder extends SparkSqlAstBuilder {
       createView(
         ctx,
         ctx.tableIdentifier,
+        comment = Option(ctx.STRING).map(string),
         schema,
         ctx.query,
         Option(ctx.tablePropertyList).map(visitTablePropertyList).getOrElse(Map.empty),
@@ -278,6 +271,7 @@ class HiveSqlAstBuilder extends SparkSqlAstBuilder {
     createView(
       ctx,
       ctx.tableIdentifier,
+      comment = None,
       Seq.empty,
       ctx.query,
       Map.empty,
@@ -291,6 +285,7 @@ class HiveSqlAstBuilder extends SparkSqlAstBuilder {
   private def createView(
       ctx: ParserRuleContext,
       name: TableIdentifierContext,
+      comment: Option[String],
       schema: Seq[CatalogColumn],
       query: QueryContext,
       properties: Map[String, String],
@@ -304,7 +299,8 @@ class HiveSqlAstBuilder extends SparkSqlAstBuilder {
       storage = EmptyStorageFormat,
       properties = properties,
       viewOriginalText = sql,
-      viewText = sql)
+      viewText = sql,
+      comment = comment)
     CreateView(tableDesc, plan(query), allowExist, replace, command(ctx))
   }
 

sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveDDLCommandSuite.scala

@@ -236,15 +236,6 @@ class HiveDDLCommandSuite extends PlanTest {
           |FROM testData
         """.stripMargin)
     }
-    intercept[ParseException] {
-      parser.parsePlan(
-        """
-          |CREATE OR REPLACE VIEW IF NOT EXISTS view1 (col1, col3)
-          |COMMENT 'blabla'
-          |TBLPROPERTIES('prop1Key'="prop1Val")
-          |AS SELECT * FROM tab1
-        """.stripMargin)
-    }
   }
 
   test("Invalid interval term should throw AnalysisException") {
@@ -532,6 +523,7 @@ class HiveDDLCommandSuite extends PlanTest {
       """
         |CREATE OR REPLACE VIEW IF NOT EXISTS view1
         |(col1, col3)
+        |COMMENT 'BLABLA'
         |TBLPROPERTIES('prop1Key'="prop1Val")
         |AS SELECT * FROM tab1
       """.stripMargin
@@ -551,6 +543,7 @@ class HiveDDLCommandSuite extends PlanTest {
     assert(desc.storage.outputFormat.isEmpty)
     assert(desc.storage.serde.isEmpty)
     assert(desc.properties == Map("prop1Key" -> "prop1Val"))
+    assert(desc.comment == Option("BLABLA"))
   }
 
   test("create view -- partitioned view") {

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveDDLSuite.scala

@@ -110,6 +110,22 @@ class HiveDDLSuite extends QueryTest with SQLTestUtils with TestHiveSingleton {
     }
   }
 
+  test("create table and view with comment") {
+    val catalog = hiveContext.sessionState.catalog
+    val tabName = "tab1"
+    withTable(tabName) {
+      sql(s"CREATE TABLE $tabName(c1 int) COMMENT 'BLABLA'")
+      val viewName = "view1"
+      withView(viewName) {
+        sql(s"CREATE VIEW $viewName COMMENT 'no comment' AS SELECT * FROM $tabName")
+        val tableMetadata = catalog.getTableMetadata(TableIdentifier(tabName, Some("default")))
+        val viewMetadata = catalog.getTableMetadata(TableIdentifier(viewName, Some("default")))
+        assert(tableMetadata.properties.get("comment") == Option("BLABLA"))
+        assert(viewMetadata.properties.get("comment") == Option("no comment"))
+      }
+    }
+  }
+
   test("drop views") {
     withTable("tab1") {
       val tabName = "tab1"