Updated.

Author: viirya

sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4

@@ -196,7 +196,7 @@ statement
     | SHOW PARTITIONS multipartIdentifier partitionSpec?               #showPartitions
     | SHOW identifier? FUNCTIONS
         (LIKE? (multipartIdentifier | pattern=STRING))?                #showFunctions
-    | SHOW CREATE TABLE multipartIdentifier (AS SPARK)                 #showCreateTable
+    | SHOW CREATE TABLE multipartIdentifier (AS SPARK)?                #showCreateTable
     | SHOW CURRENT NAMESPACE                                           #showCurrentNamespace
     | (DESC | DESCRIBE) FUNCTION EXTENDED? describeFuncName            #describeFunction
     | (DESC | DESCRIBE) database EXTENDED? db=errorCapturingIdentifier #describeDatabase

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala

@@ -2982,7 +2982,7 @@ class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging
    * Creates a [[ShowCreateTableStatement]]
    */
   override def visitShowCreateTable(ctx: ShowCreateTableContext): LogicalPlan = withOrigin(ctx) {
-    ShowCreateTableStatement(visitMultipartIdentifier(ctx.multipartIdentifier()))
+    ShowCreateTableStatement(visitMultipartIdentifier(ctx.multipartIdentifier()), ctx.SPARK != null)
   }
 
   /**

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/statements.scala

@@ -382,7 +382,9 @@ case class LoadDataStatement(
 /**
  * A SHOW CREATE TABLE statement, as parsed from SQL.
  */
-case class ShowCreateTableStatement(tableName: Seq[String]) extends ParsedStatement
+case class ShowCreateTableStatement(
+    tableName: Seq[String],
+    asSpark: Boolean = false) extends ParsedStatement
 
 /**
  * A CACHE TABLE statement, as parsed from SQL

sql/core/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveSessionCatalog.scala

@@ -328,10 +328,14 @@ class ResolveSessionCatalog(
         isOverwrite,
         partition)
 
-    case ShowCreateTableStatement(tableName) =>
+    case ShowCreateTableStatement(tableName, asSpark) if !asSpark =>
       val v1TableName = parseV1Table(tableName, "SHOW CREATE TABLE")
       ShowCreateTableCommand(v1TableName.asTableIdentifier)
 
+    case ShowCreateTableStatement(tableName, asSpark) if asSpark =>
+      val v1TableName = parseV1Table(tableName, "SHOW CREATE TABLE AS SPARK")
+      ShowCreateTableAsSparkCommand(v1TableName.asTableIdentifier)
+
     case CacheTableStatement(tableName, plan, isLazy, options) =>
       val v1TableName = parseV1Table(tableName, "CACHE TABLE")
       CacheTableCommand(v1TableName.asTableIdentifier, plan, isLazy, options)