[SPARK-17180][SPARK-17309][SPARK-17323][SQL] create AlterViewAsCommand to handle ALTER VIEW AS

## What changes were proposed in this pull request?

Currently we use `CreateViewCommand` to implement ALTER VIEW AS, which has 3 bugs:

1. SPARK-17180: ALTER VIEW AS should alter temp view if view name has no database part and temp view exists
2. SPARK-17309: ALTER VIEW AS should issue exception if view does not exist.
3. SPARK-17323: ALTER VIEW AS should keep the previous table properties, comment, create_time, etc.

The root cause is, ALTER VIEW AS is quite different from CREATE VIEW, we need different code path to handle them. However, in `CreateViewCommand`, there is no way to distinguish ALTER VIEW AS and CREATE VIEW, we have to introduce extra flag. But instead of doing this, I think a more natural way is to separate the ALTER VIEW AS logic into a new command.

## How was this patch tested?

new tests in SQLViewSuite

Author: Wenchen Fan <wenchen@databricks.com>

Closes #14874 from cloud-fan/minor4.

1 files changed, 74 insertions, 3 deletions

diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLViewSuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLViewSuite.scala
index 6a80664417..bc999d4724 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLViewSuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLViewSuite.scala
@@ -18,6 +18,8 @@
 package org.apache.spark.sql.hive.execution
 
 import org.apache.spark.sql.{AnalysisException, QueryTest, Row, SaveMode}
+import org.apache.spark.sql.catalyst.TableIdentifier
+import org.apache.spark.sql.catalyst.analysis.NoSuchTableException
 import org.apache.spark.sql.hive.test.TestHiveSingleton
 import org.apache.spark.sql.test.SQLTestUtils
 
@@ -60,15 +62,15 @@ class SQLViewSuite extends QueryTest with SQLTestUtils with TestHiveSingleton {
       var e = intercept[AnalysisException] {
         sql("CREATE OR REPLACE VIEW tab1 AS SELECT * FROM jt")
       }.getMessage
-      assert(e.contains("The following is an existing table, not a view: `default`.`tab1`"))
+      assert(e.contains("`default`.`tab1` is not a view"))
       e = intercept[AnalysisException] {
         sql("CREATE VIEW tab1 AS SELECT * FROM jt")
       }.getMessage
-      assert(e.contains("The following is an existing table, not a view: `default`.`tab1`"))
+      assert(e.contains("`default`.`tab1` is not a view"))
       e = intercept[AnalysisException] {
         sql("ALTER VIEW tab1 AS SELECT * FROM jt")
       }.getMessage
-      assert(e.contains("The following is an existing table, not a view: `default`.`tab1`"))
+      assert(e.contains("`default`.`tab1` is not a view"))
     }
   }
 
@@ -274,6 +276,75 @@ class SQLViewSuite extends QueryTest with SQLTestUtils with TestHiveSingleton {
     }
   }
 
+  test("should not allow ALTER VIEW AS when the view does not exist") {
+    intercept[NoSuchTableException](
+      sql("ALTER VIEW testView AS SELECT 1, 2")
+    )
+
+    intercept[NoSuchTableException](
+      sql("ALTER VIEW default.testView AS SELECT 1, 2")
+    )
+  }
+
+  test("ALTER VIEW AS should try to alter temp view first if view name has no database part") {
+    withView("test_view") {
+      withTempView("test_view") {
+        sql("CREATE VIEW test_view AS SELECT 1 AS a, 2 AS b")
+        sql("CREATE TEMP VIEW test_view AS SELECT 1 AS a, 2 AS b")
+
+        sql("ALTER VIEW test_view AS SELECT 3 AS i, 4 AS j")
+
+        // The temporary view should be updated.
+        checkAnswer(spark.table("test_view"), Row(3, 4))
+
+        // The permanent view should stay same.
+        checkAnswer(spark.table("default.test_view"), Row(1, 2))
+      }
+    }
+  }
+
+  test("ALTER VIEW AS should alter permanent view if view name has database part") {
+    withView("test_view") {
+      withTempView("test_view") {
+        sql("CREATE VIEW test_view AS SELECT 1 AS a, 2 AS b")
+        sql("CREATE TEMP VIEW test_view AS SELECT 1 AS a, 2 AS b")
+
+        sql("ALTER VIEW default.test_view AS SELECT 3 AS i, 4 AS j")
+
+        // The temporary view should stay same.
+        checkAnswer(spark.table("test_view"), Row(1, 2))
+
+        // The permanent view should be updated.
+        checkAnswer(spark.table("default.test_view"), Row(3, 4))
+      }
+    }
+  }
+
+  test("ALTER VIEW AS should keep the previous table properties, comment, create_time, etc.") {
+    withView("test_view") {
+      sql(
+        """
+          |CREATE VIEW test_view
+          |COMMENT 'test'
+          |TBLPROPERTIES ('key' = 'a')
+          |AS SELECT 1 AS a, 2 AS b
+        """.stripMargin)
+
+      val catalog = spark.sessionState.catalog
+      val viewMeta = catalog.getTableMetadata(TableIdentifier("test_view"))
+      assert(viewMeta.comment == Some("test"))
+      assert(viewMeta.properties("key") == "a")
+
+      sql("ALTER VIEW test_view AS SELECT 3 AS i, 4 AS j")
+      val updatedViewMeta = catalog.getTableMetadata(TableIdentifier("test_view"))
+      assert(updatedViewMeta.comment == Some("test"))
+      assert(updatedViewMeta.properties("key") == "a")
+      assert(updatedViewMeta.createTime == viewMeta.createTime)
+      // The view should be updated.
+      checkAnswer(spark.table("test_view"), Row(3, 4))
+    }
+  }
+
   test("create hive view for json table") {
     // json table is not hive-compatible, make sure the new flag fix it.
     withView("testView") {