[SPARK-2658][SQL] Add rule for true = 1.

Author: Michael Armbrust <michael@databricks.com>

Closes #1556 from marmbrus/fixBooleanEqualsOne and squashes the following commits:

ad8edd4 [Michael Armbrust] Add rule for true = 1 and false = 0.

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

@@ -231,10 +231,20 @@ trait HiveTypeCoercion {
    * Changes Boolean values to Bytes so that expressions like true < false can be Evaluated.
    */
   object BooleanComparisons extends Rule[LogicalPlan] {
+    val trueValues = Seq(1, 1L, 1.toByte, 1.toShort, BigDecimal(1)).map(Literal(_))
+    val falseValues = Seq(0, 0L, 0.toByte, 0.toShort, BigDecimal(0)).map(Literal(_))
+
     def apply(plan: LogicalPlan): LogicalPlan = plan transformAllExpressions {
       // Skip nodes who's children have not been resolved yet.
       case e if !e.childrenResolved => e
-      // No need to change EqualTo operators as that actually makes sense for boolean types.
+
+      // Hive treats (true = 1) as true and (false = 0) as true.
+      case EqualTo(l @ BooleanType(), r) if trueValues.contains(r) => l
+      case EqualTo(l, r @ BooleanType()) if trueValues.contains(l) => r
+      case EqualTo(l @ BooleanType(), r) if falseValues.contains(r) => Not(l)
+      case EqualTo(l, r @ BooleanType()) if falseValues.contains(l) => Not(r)
+
+      // No need to change other EqualTo operators as that actually makes sense for boolean types.
       case e: EqualTo => e
       // Otherwise turn them to Byte types so that there exists and ordering.
       case p: BinaryComparison

sql/hive/src/test/resources/golden/boolean = number-0-6b6975fa1892cc48edd87dc0df48a7c0

+true	true	true	true	true	true	false	false	false	false	false	false	false	false	false	false	false	false	true	true	true	true	true	true	false	false	false	false	false	false	false	false	false	false	false	false

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveQuerySuite.scala

@@ -30,6 +30,18 @@ case class TestData(a: Int, b: String)
  */
 class HiveQuerySuite extends HiveComparisonTest {
 
+  createQueryTest("boolean = number",
+    """
+      |SELECT
+      |  1 = true, 1L = true, 1Y = true, true = 1, true = 1L, true = 1Y,
+      |  0 = true, 0L = true, 0Y = true, true = 0, true = 0L, true = 0Y,
+      |  1 = false, 1L = false, 1Y = false, false = 1, false = 1L, false = 1Y,
+      |  0 = false, 0L = false, 0Y = false, false = 0, false = 0L, false = 0Y,
+      |  2 = true, 2L = true, 2Y = true, true = 2, true = 2L, true = 2Y,
+      |  2 = false, 2L = false, 2Y = false, false = 2, false = 2L, false = 2Y
+      |FROM src LIMIT 1
+    """.stripMargin)
+
   test("CREATE TABLE AS runs once") {
     hql("CREATE TABLE foo AS SELECT 1 FROM src LIMIT 1").collect()
     assert(hql("SELECT COUNT(*) FROM foo").collect().head.getLong(0) === 1,