[SPARK-29527][SQL] SHOW CREATE TABLE should look up catalog/table like v2 commands

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

@@ -201,7 +201,7 @@ statement
     | SHOW PARTITIONS multipartIdentifier partitionSpec?               #showPartitions
     | SHOW identifier? FUNCTIONS
         (LIKE? (qualifiedName | pattern=STRING))?                      #showFunctions
-    | SHOW CREATE TABLE tableIdentifier                                #showCreateTable
+    | SHOW CREATE TABLE multipartIdentifier                            #showCreateTable
     | (DESC | DESCRIBE) FUNCTION EXTENDED? describeFuncName            #describeFunction
     | (DESC | DESCRIBE) database EXTENDED? db=errorCapturingIdentifier #describeDatabase
     | (DESC | DESCRIBE) TABLE? option=(EXTENDED | FORMATTED)?

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

@@ -2797,6 +2797,13 @@ class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging
     RepairTableStatement(visitMultipartIdentifier(ctx.multipartIdentifier()))
   }
 
+  /**
+   * Creates a [[ShowCreateTableStatement]]
+   */
+  override def visitShowCreateTable(ctx: ShowCreateTableContext): LogicalPlan = withOrigin(ctx) {
+    ShowCreateTableStatement(visitMultipartIdentifier(ctx.multipartIdentifier()))
+  }
+
   /**
    * Create a [[CacheTableStatement]].
    *

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

@@ -330,6 +330,11 @@ case class AnalyzeColumnStatement(
  */
 case class RepairTableStatement(tableName: Seq[String]) extends ParsedStatement
 
+/**
+ * A SHOW CREATE TABLE statement, as parsed from SQL.
+ */
+case class ShowCreateTableStatement(tableName: Seq[String]) extends ParsedStatement
+
 /**
  * A CACHE TABLE statement, as parsed from SQL
  */

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/parser/DDLParserSuite.scala

@@ -1045,6 +1045,12 @@ class DDLParserSuite extends AnalysisTest {
       RepairTableStatement(Seq("a", "b", "c")))
   }
 
+  test("SHOW CREATE table") {
+    comparePlans(
+      parsePlan("SHOW CREATE TABLE a.b.c"),
+      ShowCreateTableStatement(Seq("a", "b", "c")))
+  }
+
   test("CACHE TABLE") {
     comparePlans(
       parsePlan("CACHE TABLE a.b.c"),

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

@@ -24,7 +24,7 @@ import org.apache.spark.sql.catalyst.plans.logical._
 import org.apache.spark.sql.catalyst.rules.Rule
 import org.apache.spark.sql.connector.catalog.{CatalogManager, CatalogPlugin, LookupCatalog, TableChange, V1Table}
 import org.apache.spark.sql.connector.expressions.Transform
-import org.apache.spark.sql.execution.command.{AlterTableAddColumnsCommand, AlterTableRecoverPartitionsCommand, AlterTableSetLocationCommand, AlterTableSetPropertiesCommand, AlterTableUnsetPropertiesCommand, AnalyzeColumnCommand, AnalyzePartitionCommand, AnalyzeTableCommand, CacheTableCommand, CreateDatabaseCommand, DescribeColumnCommand, DescribeTableCommand, DropTableCommand, ShowPartitionsCommand, ShowTablesCommand, TruncateTableCommand, UncacheTableCommand}
+import org.apache.spark.sql.execution.command.{AlterTableAddColumnsCommand, AlterTableRecoverPartitionsCommand, AlterTableSetLocationCommand, AlterTableSetPropertiesCommand, AlterTableUnsetPropertiesCommand, AnalyzeColumnCommand, AnalyzePartitionCommand, AnalyzeTableCommand, CacheTableCommand, CreateDatabaseCommand, DescribeColumnCommand, DescribeTableCommand, DropTableCommand, ShowCreateTableCommand, ShowPartitionsCommand, ShowTablesCommand, TruncateTableCommand, UncacheTableCommand}
 import org.apache.spark.sql.execution.datasources.{CreateTable, DataSource, RefreshTable}
 import org.apache.spark.sql.execution.datasources.v2.FileDataSourceV2
 import org.apache.spark.sql.internal.SQLConf
@@ -299,6 +299,10 @@ class ResolveSessionCatalog(
         v1TableName.asTableIdentifier,
         "MSCK REPAIR TABLE")
 
+    case ShowCreateTableStatement(tableName) =>
+      val v1TableName = parseV1Table(tableName, "SHOW CREATE TABLE")
+      ShowCreateTableCommand(v1TableName.asTableIdentifier)
+
     case CacheTableStatement(tableName, plan, isLazy, options) =>
       val v1TableName = parseV1Table(tableName, "CACHE TABLE")
       CacheTableCommand(v1TableName.asTableIdentifier, plan, isLazy, options)

sql/core/src/main/scala/org/apache/spark/sql/execution/SparkSqlParser.scala

@@ -135,14 +135,6 @@ class SparkSqlAstBuilder(conf: SQLConf) extends AstBuilder(conf) {
     ShowColumnsCommand(Option(ctx.db).map(_.getText), visitTableIdentifier(ctx.tableIdentifier))
   }
 
-  /**
-   * Creates a [[ShowCreateTableCommand]]
-   */
-  override def visitShowCreateTable(ctx: ShowCreateTableContext): LogicalPlan = withOrigin(ctx) {
-    val table = visitTableIdentifier(ctx.tableIdentifier())
-    ShowCreateTableCommand(table)
-  }
-
   /**
    * Create a [[RefreshResource]] logical plan.
    */

sql/core/src/test/scala/org/apache/spark/sql/connector/DataSourceV2SQLSuite.scala

@@ -1268,6 +1268,14 @@ class DataSourceV2SQLSuite
     }
   }
 
+  test("SHOW CREATE TABLE") {
+    val t = "testcat.ns1.ns2.tbl"
+    withTable(t) {
+      spark.sql(s"CREATE TABLE $t (id bigint, data string) USING foo")
+      testV1Command("SHOW CREATE TABLE", t)
+    }
+  }
+
   test("CACHE TABLE") {
     val t = "testcat.ns1.ns2.tbl"
     withTable(t) {