[SPARK-17750][SQL] Fix CREATE VIEW with INTERVAL arithmetic.

## What changes were proposed in this pull request?

Currently, Spark raises `RuntimeException` when creating a view with timestamp with INTERVAL arithmetic like the following. The root cause is the arithmetic expression, `TimeAdd`, was transformed into `timeadd` function as a VIEW definition. This PR fixes the SQL definition of `TimeAdd` and `TimeSub` expressions.

```scala
scala> sql("CREATE TABLE dates (ts TIMESTAMP)")

scala> sql("CREATE VIEW view1 AS SELECT ts + INTERVAL 1 DAY FROM dates")
java.lang.RuntimeException: Failed to analyze the canonicalized SQL: ...
```

## How was this patch tested?

Pass Jenkins with a new testcase.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #15318 from dongjoon-hyun/SPARK-17750.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala

@@ -682,6 +682,7 @@ case class TimeAdd(start: Expression, interval: Expression)
   override def right: Expression = interval
 
   override def toString: String = s"$left + $right"
+  override def sql: String = s"${left.sql} + ${right.sql}"
   override def inputTypes: Seq[AbstractDataType] = Seq(TimestampType, CalendarIntervalType)
 
   override def dataType: DataType = TimestampType
@@ -762,6 +763,7 @@ case class TimeSub(start: Expression, interval: Expression)
   override def right: Expression = interval
 
   override def toString: String = s"$left - $right"
+  override def sql: String = s"${left.sql} - ${right.sql}"
   override def inputTypes: Seq[AbstractDataType] = Seq(TimestampType, CalendarIntervalType)
 
   override def dataType: DataType = TimestampType

sql/hive/src/test/resources/sqlgen/interval_arithmetic.sql

+-- This file is automatically generated by LogicalPlanToSQLSuite.
+select ts + interval 1 day, ts + interval 2 days,
+       ts - interval 1 day, ts - interval 2 days,
+       ts + interval '1' day, ts + interval '2' days,
+       ts - interval '1' day, ts - interval '2' days
+from dates
+--------------------------------------------------------------------------------
+SELECT `gen_attr_0` AS `CAST(ts + interval 1 days AS TIMESTAMP)`, `gen_attr_2` AS `CAST(ts + interval 2 days AS TIMESTAMP)`, `gen_attr_3` AS `CAST(ts - interval 1 days AS TIMESTAMP)`, `gen_attr_4` AS `CAST(ts - interval 2 days AS TIMESTAMP)`, `gen_attr_5` AS `CAST(ts + interval 1 days AS TIMESTAMP)`, `gen_attr_6` AS `CAST(ts + interval 2 days AS TIMESTAMP)`, `gen_attr_7` AS `CAST(ts - interval 1 days AS TIMESTAMP)`, `gen_attr_8` AS `CAST(ts - interval 2 days AS TIMESTAMP)` FROM (SELECT CAST(`gen_attr_1` + interval 1 days AS TIMESTAMP) AS `gen_attr_0`, CAST(`gen_attr_1` + interval 2 days AS TIMESTAMP) AS `gen_attr_2`, CAST(`gen_attr_1` - interval 1 days AS TIMESTAMP) AS `gen_attr_3`, CAST(`gen_attr_1` - interval 2 days AS TIMESTAMP) AS `gen_attr_4`, CAST(`gen_attr_1` + interval 1 days AS TIMESTAMP) AS `gen_attr_5`, CAST(`gen_attr_1` + interval 2 days AS TIMESTAMP) AS `gen_attr_6`, CAST(`gen_attr_1` - interval 1 days AS TIMESTAMP) AS `gen_attr_7`, CAST(`gen_attr_1` - interval 2 days AS TIMESTAMP) AS `gen_attr_8` FROM (SELECT `ts` AS `gen_attr_1` FROM `default`.`dates`) AS gen_subquery_0) AS gen_subquery_1

sql/hive/src/test/scala/org/apache/spark/sql/catalyst/ExpressionSQLBuilderSuite.scala

@@ -20,7 +20,9 @@ package org.apache.spark.sql.catalyst
 import java.sql.Timestamp
 
 import org.apache.spark.sql.catalyst.dsl.expressions._
-import org.apache.spark.sql.catalyst.expressions.{If, Literal, SpecifiedWindowFrame, WindowSpecDefinition}
+import org.apache.spark.sql.catalyst.expressions.{If, Literal, SpecifiedWindowFrame, TimeAdd,
+  TimeSub, WindowSpecDefinition}
+import org.apache.spark.unsafe.types.CalendarInterval
 
 class ExpressionSQLBuilderSuite extends SQLBuilderTest {
   test("literal") {
@@ -119,4 +121,18 @@ class ExpressionSQLBuilderSuite extends SQLBuilderTest {
       s"(PARTITION BY `a`, `b` ORDER BY `c` ASC NULLS FIRST, `d` DESC NULLS LAST $frame)"
     )
   }
+
+  test("interval arithmetic") {
+    val interval = Literal(new CalendarInterval(0, CalendarInterval.MICROS_PER_DAY))
+
+    checkSQL(
+      TimeAdd('a, interval),
+      "`a` + interval 1 days"
+    )
+
+    checkSQL(
+      TimeSub('a, interval),
+      "`a` - interval 1 days"
+    )
+  }
 }

sql/hive/src/test/scala/org/apache/spark/sql/catalyst/LogicalPlanToSQLSuite.scala

@@ -1145,4 +1145,20 @@ class LogicalPlanToSQLSuite extends SQLBuilderTest with SQLTestUtils {
       """.stripMargin,
       "inline_tables")
   }
+
+  test("SPARK-17750 - interval arithmetic") {
+    withTable("dates") {
+      sql("create table dates (ts timestamp)")
+      checkSQL(
+        """
+          |select ts + interval 1 day, ts + interval 2 days,
+          |       ts - interval 1 day, ts - interval 2 days,
+          |       ts + interval '1' day, ts + interval '2' days,
+          |       ts - interval '1' day, ts - interval '2' days
+          |from dates
+        """.stripMargin,
+        "interval_arithmetic"
+      )
+    }
+  }
 }