[SPARK-16457][SQL] Fix Wrong Messages when CTAS with a Partition By Clause

#### What changes were proposed in this pull request?
When doing a CTAS with a Partition By clause, we got a wrong error message.

For example,
```SQL
CREATE TABLE gen__tmp
PARTITIONED BY (key string)
AS SELECT key, value FROM mytable1
```
The error message we get now is like
```
Operation not allowed: Schema may not be specified in a Create Table As Select (CTAS) statement(line 2, pos 0)
```

However, based on the code, the message we should get is like
```
Operation not allowed: A Create Table As Select (CTAS) statement is not allowed to create a partitioned table using Hive's file formats. Please use the syntax of "CREATE TABLE tableName USING dataSource OPTIONS (...) PARTITIONED BY ...\" to create a partitioned table through a CTAS statement.(line 2, pos 0)
```

Currently, partitioning columns is part of the schema. This PR fixes the bug by changing the detection orders.

#### How was this patch tested?
Added test cases.

Author: gatorsmile <gatorsmile@gmail.com>

Closes #14113 from gatorsmile/ctas.

1 files changed, 26 insertions, 10 deletions

diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala
index cba6aa53f1..b659325a62 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala
@@ -642,19 +642,35 @@ class SQLQuerySuite extends QueryTest with SQLTestUtils with TestHiveSingleton {
   }
 
   test("specifying the column list for CTAS") {
-    Seq((1, "111111"), (2, "222222")).toDF("key", "value").createOrReplaceTempView("mytable1")
+    withTempView("mytable1") {
+      Seq((1, "111111"), (2, "222222")).toDF("key", "value").createOrReplaceTempView("mytable1")
+      withTable("gen__tmp") {
+        sql("create table gen__tmp as select key as a, value as b from mytable1")
+        checkAnswer(
+          sql("SELECT a, b from gen__tmp"),
+          sql("select key, value from mytable1").collect())
+      }
 
-    sql("create table gen__tmp as select key as a, value as b from mytable1")
-    checkAnswer(
-      sql("SELECT a, b from gen__tmp"),
-      sql("select key, value from mytable1").collect())
-    sql("DROP TABLE gen__tmp")
+      withTable("gen__tmp") {
+        val e = intercept[AnalysisException] {
+          sql("create table gen__tmp(a int, b string) as select key, value from mytable1")
+        }.getMessage
+        assert(e.contains("Schema may not be specified in a Create Table As Select (CTAS)"))
+      }
 
-    intercept[AnalysisException] {
-      sql("create table gen__tmp(a int, b string) as select key, value from mytable1")
+      withTable("gen__tmp") {
+        val e = intercept[AnalysisException] {
+          sql(
+            """
+              |CREATE TABLE gen__tmp
+              |PARTITIONED BY (key string)
+              |AS SELECT key, value FROM mytable1
+            """.stripMargin)
+        }.getMessage
+        assert(e.contains("A Create Table As Select (CTAS) statement is not allowed to " +
+          "create a partitioned table using Hive's file formats"))
+      }
     }
-
-    sql("drop table mytable1")
   }
 
   test("command substitution") {