[SPARK-20023][SQL] Output table comment for DESC FORMATTED

### What changes were proposed in this pull request?
Currently, `DESC FORMATTED` did not output the table comment, unlike what `DESC EXTENDED` does. This PR is to fix it.

Also correct the following displayed names in `DESC FORMATTED`, for being consistent with `DESC EXTENDED`
- `"Create Time:"` -> `"Created:"`
- `"Last Access Time:"` -> `"Last Access:"`

### How was this patch tested?
Added test cases in `describe.sql`

Author: Xiao Li <gatorsmile@gmail.com>

Closes #17381 from gatorsmile/descFormattedTableComment.

sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala

@@ -568,11 +568,12 @@ case class DescribeTableCommand(
     append(buffer, "# Detailed Table Information", "", "")
     append(buffer, "Database:", table.database, "")
     append(buffer, "Owner:", table.owner, "")
-    append(buffer, "Create Time:", new Date(table.createTime).toString, "")
-    append(buffer, "Last Access Time:", new Date(table.lastAccessTime).toString, "")
+    append(buffer, "Created:", new Date(table.createTime).toString, "")
+    append(buffer, "Last Access:", new Date(table.lastAccessTime).toString, "")
     append(buffer, "Location:", table.storage.locationUri.map(CatalogUtils.URIToString(_))
       .getOrElse(""), "")
     append(buffer, "Table Type:", table.tableType.name, "")
+    append(buffer, "Comment:", table.comment.getOrElse(""), "")
     table.stats.foreach(s => append(buffer, "Statistics:", s.simpleString, ""))
 
     append(buffer, "Table Parameters:", "", "")

sql/core/src/test/resources/sql-tests/inputs/describe.sql

-CREATE TABLE t (a STRING, b INT, c STRING, d STRING) USING parquet PARTITIONED BY (c, d);
+CREATE TABLE t (a STRING, b INT, c STRING, d STRING) USING parquet PARTITIONED BY (c, d) COMMENT 'table_comment';
 
 ALTER TABLE t ADD PARTITION (c='Us', d=1);
 
@@ -8,15 +8,15 @@ DESC t;
 
 DESC TABLE t;
 
--- Ignore these because there exist timestamp results, e.g., `Create Table`.
--- DESC EXTENDED t;
--- DESC FORMATTED t;
+DESC FORMATTED t;
+
+DESC EXTENDED t;
 
 DESC t PARTITION (c='Us', d=1);
 
--- Ignore these because there exist timestamp results, e.g., transient_lastDdlTime.
--- DESC EXTENDED t PARTITION (c='Us', d=1);
--- DESC FORMATTED t PARTITION (c='Us', d=1);
+DESC EXTENDED t PARTITION (c='Us', d=1);
+
+DESC FORMATTED t PARTITION (c='Us', d=1);
 
 -- NoSuchPartitionException: Partition not found in table
 DESC t PARTITION (c='Us', d=2);

sql/core/src/test/resources/sql-tests/results/describe.sql.out

 -- Automatically generated by SQLQueryTestSuite
--- Number of queries: 10
+-- Number of queries: 14
 
 
 -- !query 0
-CREATE TABLE t (a STRING, b INT, c STRING, d STRING) USING parquet PARTITIONED BY (c, d)
+CREATE TABLE t (a STRING, b INT, c STRING, d STRING) USING parquet PARTITIONED BY (c, d) COMMENT 'table_comment'
 -- !query 0 schema
 struct<>
 -- !query 0 output
@@ -64,12 +64,25 @@ d                   	string
 
 
 -- !query 5
-DESC t PARTITION (c='Us', d=1)
+DESC FORMATTED t
 -- !query 5 schema
 struct<col_name:string,data_type:string,comment:string>
 -- !query 5 output
+# Detailed Table Information	                    	                    
 # Partition Information	                    	                    
+# Storage Information	                    	                    
 # col_name          	data_type           	comment             
+Comment:            	table_comment       	                    
+Compressed:         	No                  	                    
+Created: 
+Database:           	default             	                    
+Last Access: 
+Location: sql/core/spark-warehouse/t	                    
+Owner:              	                    	                    
+Partition Provider: 	Catalog             	                    
+Storage Desc Parameters:	                    	                    
+Table Parameters:   	                    	                    
+Table Type:         	MANAGED             	                    
 a                   	string              	                    
 b                   	int                 	                    
 c                   	string              	                    
@@ -79,30 +92,114 @@ d                   	string
 
 
 -- !query 6
-DESC t PARTITION (c='Us', d=2)
+DESC EXTENDED t
 -- !query 6 schema
-struct<>
+struct<col_name:string,data_type:string,comment:string>
 -- !query 6 output
+# Detailed Table Information	CatalogTable(
+	Table: `default`.`t`
+	Created: 
+	Last Access: 
+	Type: MANAGED
+	Schema: [StructField(a,StringType,true), StructField(b,IntegerType,true), StructField(c,StringType,true), StructField(d,StringType,true)]
+	Provider: parquet
+	Partition Columns: [`c`, `d`]
+	Comment: table_comment
+	Storage(Location: sql/core/spark-warehouse/t)
+	Partition Provider: Catalog)	                    
+# Partition Information	                    	                    
+# col_name          	data_type           	comment             
+a                   	string              	                    
+b                   	int                 	                    
+c                   	string              	                    
+c                   	string              	                    
+d                   	string              	                    
+d                   	string
+
+
+-- !query 7
+DESC t PARTITION (c='Us', d=1)
+-- !query 7 schema
+struct<col_name:string,data_type:string,comment:string>
+-- !query 7 output
+# Partition Information	                    	                    
+# col_name          	data_type           	comment             
+a                   	string              	                    
+b                   	int                 	                    
+c                   	string              	                    
+c                   	string              	                    
+d                   	string              	                    
+d                   	string
+
+
+-- !query 8
+DESC EXTENDED t PARTITION (c='Us', d=1)
+-- !query 8 schema
+struct<col_name:string,data_type:string,comment:string>
+-- !query 8 output
+# Partition Information	                    	                    
+# col_name          	data_type           	comment             
+Detailed Partition Information CatalogPartition(
+	Partition Values: [c=Us, d=1]
+	Storage(Location: sql/core/spark-warehouse/t/c=Us/d=1)
+	Partition Parameters:{})	                    	                    
+a                   	string              	                    
+b                   	int                 	                    
+c                   	string              	                    
+c                   	string              	                    
+d                   	string              	                    
+d                   	string
+
+
+-- !query 9
+DESC FORMATTED t PARTITION (c='Us', d=1)
+-- !query 9 schema
+struct<col_name:string,data_type:string,comment:string>
+-- !query 9 output
+# Detailed Partition Information	                    	                    
+# Partition Information	                    	                    
+# Storage Information	                    	                    
+# col_name          	data_type           	comment             
+Compressed:         	No                  	                    
+Database:           	default             	                    
+Location: sql/core/spark-warehouse/t/c=Us/d=1	                    
+Partition Parameters:	                    	                    
+Partition Value:    	[Us, 1]             	                    
+Storage Desc Parameters:	                    	                    
+Table:              	t                   	                    
+a                   	string              	                    
+b                   	int                 	                    
+c                   	string              	                    
+c                   	string              	                    
+d                   	string              	                    
+d                   	string
+
+
+-- !query 10
+DESC t PARTITION (c='Us', d=2)
+-- !query 10 schema
+struct<>
+-- !query 10 output
 org.apache.spark.sql.catalyst.analysis.NoSuchPartitionException
 Partition not found in table 't' database 'default':
 c -> Us
 d -> 2;
 
 
--- !query 7
+-- !query 11
 DESC t PARTITION (c='Us')
--- !query 7 schema
+-- !query 11 schema
 struct<>
--- !query 7 output
+-- !query 11 output
 org.apache.spark.sql.AnalysisException
 Partition spec is invalid. The spec (c) must match the partition spec (c, d) defined in table '`default`.`t`';
 
 
--- !query 8
+-- !query 12
 DESC t PARTITION (c='Us', d)
--- !query 8 schema
+-- !query 12 schema
 struct<>
--- !query 8 output
+-- !query 12 output
 org.apache.spark.sql.catalyst.parser.ParseException
 
 PARTITION specification is incomplete: `d`(line 1, pos 0)
@@ -112,9 +209,9 @@ DESC t PARTITION (c='Us', d)
 ^^^
 
 
--- !query 9
+-- !query 13
 DROP TABLE t
--- !query 9 schema
+-- !query 13 schema
 struct<>
--- !query 9 output
+-- !query 13 output
 

sql/core/src/test/scala/org/apache/spark/sql/SQLQueryTestSuite.scala

@@ -223,9 +223,9 @@ class SQLQueryTestSuite extends QueryTest with SharedSQLContext {
       val schema = df.schema
       // Get answer, but also get rid of the #1234 expression ids that show up in explain plans
       val answer = df.queryExecution.hiveResultString().map(_.replaceAll("#\\d+", "#x")
-        .replaceAll("Location: .*/sql/core/", "Location: sql/core/")
-        .replaceAll("Created: .*\n", "Created: \n")
-        .replaceAll("Last Access: .*\n", "Last Access: \n"))
+        .replaceAll("Location:.*/sql/core/", "Location: sql/core/")
+        .replaceAll("Created: .*", "Created: ")
+        .replaceAll("Last Access: .*", "Last Access: "))
 
       // If the output is not pre-sorted, sort it.
       if (isSorted(df.queryExecution.analyzed)) (schema, answer) else (schema, answer.sorted)