[SPARK-20909][SQL] Add build-int SQL function - DAYOFWEEK

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala

@@ -359,6 +359,7 @@ object FunctionRegistry {
     expression[ToUTCTimestamp]("to_utc_timestamp"),
     expression[TruncDate]("trunc"),
     expression[UnixTimestamp]("unix_timestamp"),
+    expression[DayOfWeek]("dayofweek"),
     expression[WeekOfYear]("weekofyear"),
     expression[Year]("year"),
     expression[TimeWindow]("window"),

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

@@ -402,6 +402,44 @@ case class DayOfMonth(child: Expression) extends UnaryExpression with ImplicitCa
   }
 }
 
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+  usage = "_FUNC_(date) - Returns the weekday index for date/timestamp (1 = Sunday, 2 = Monday, ..., 7 = Saturday).",
+  extended = """
+    Examples:
+      > SELECT _FUNC_('2009-07-30');
+       5
+  """)
+// scalastyle:on line.size.limit
+case class DayOfWeek(child: Expression) extends UnaryExpression with ImplicitCastInputTypes {
+
+  override def inputTypes: Seq[AbstractDataType] = Seq(DateType)
+
+  override def dataType: DataType = IntegerType
+
+  @transient private lazy val c = {
+    Calendar.getInstance(DateTimeUtils.getTimeZone("UTC"))
+  }
+
+  override protected def nullSafeEval(date: Any): Any = {
+    c.setTimeInMillis(date.asInstanceOf[Int] * 1000L * 3600L * 24L)
+    c.get(Calendar.DAY_OF_WEEK)
+  }
+
+  override protected def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+    nullSafeCodeGen(ctx, ev, time => {
+      val cal = classOf[Calendar].getName
+      val c = ctx.freshName("cal")
+      val dtu = DateTimeUtils.getClass.getName.stripSuffix("$")
+      ctx.addMutableState(cal, c, s"""$c = $cal.getInstance($dtu.getTimeZone("UTC"));""")
+      s"""
+        $c.setTimeInMillis($time * 1000L * 3600L * 24L);
+        ${ev.value} = $c.get($cal.DAY_OF_WEEK);
+      """
+    })
+  }
+}
+
 @ExpressionDescription(
   usage = "_FUNC_(date) - Returns the week of the year of the given date.",
   extended = """

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/DateExpressionsSuite.scala

@@ -196,6 +196,20 @@ class DateExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
     }
   }
 
+  test("DayOfWeek") {
+    checkEvaluation(DayOfWeek(Literal.create(null, DateType)), null)
+    checkEvaluation(DayOfWeek(Literal(d)), Calendar.WEDNESDAY)
+    checkEvaluation(DayOfWeek(Cast(Literal(sdfDate.format(d)), DateType, gmtId)),
+      Calendar.WEDNESDAY)
+    checkEvaluation(DayOfWeek(Cast(Literal(ts), DateType, gmtId)), Calendar.FRIDAY)
+    checkEvaluation(DayOfWeek(Cast(Literal("2011-05-06"), DateType, gmtId)), Calendar.FRIDAY)
+    checkEvaluation(DayOfWeek(Literal(new Date(sdf.parse("2017-05-27 13:10:15").getTime))),
+      Calendar.SATURDAY)
+    checkEvaluation(DayOfWeek(Literal(new Date(sdf.parse("1582-10-15 13:10:15").getTime))),
+      Calendar.FRIDAY)
+    checkConsistencyBetweenInterpretedAndCodegen(DayOfWeek, DateType)
+  }
+
   test("WeekOfYear") {
     checkEvaluation(WeekOfYear(Literal.create(null, DateType)), null)
     checkEvaluation(WeekOfYear(Literal(d)), 15)

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

@@ -6,3 +6,5 @@ select current_date = current_date(), current_timestamp = current_timestamp();
 select to_date(null), to_date('2016-12-31'), to_date('2016-12-31', 'yyyy-MM-dd');
 
 select to_timestamp(null), to_timestamp('2016-12-31 00:12:00'), to_timestamp('2016-12-31', 'yyyy-MM-dd');
+
+select dayofweek('2007-02-03'), dayofweek('2009-07-30'), dayofweek('2017-05-27'), dayofweek(null), dayofweek('1582-10-15 13:10:15');

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

@@ -1,5 +1,5 @@
 -- Automatically generated by SQLQueryTestSuite
--- Number of queries: 3
+-- Number of queries: 4
 
 
 -- !query 0
@@ -24,3 +24,11 @@ select to_timestamp(null), to_timestamp('2016-12-31 00:12:00'), to_timestamp('20
 struct<to_timestamp(NULL):timestamp,to_timestamp('2016-12-31 00:12:00'):timestamp,to_timestamp('2016-12-31', 'yyyy-MM-dd'):timestamp>
 -- !query 2 output
 NULL	2016-12-31 00:12:00	2016-12-31 00:00:00
+
+
+-- !query 3
+select dayofweek('2007-02-03'), dayofweek('2009-07-30'), dayofweek('2017-05-27'), dayofweek(null), dayofweek('1582-10-15 13:10:15')
+-- !query 3 schema
+struct<dayofweek(CAST(2007-02-03 AS DATE)):int,dayofweek(CAST(2009-07-30 AS DATE)):int,dayofweek(CAST(2017-05-27 AS DATE)):int,dayofweek(CAST(NULL AS DATE)):int,dayofweek(CAST(1582-10-15 13:10:15 AS DATE)):int>
+-- !query 3 output
+7	5	7	NULL	6