[FLINK-3098] [Table API] Cast Data to Long throw compile error.

This closes #1431.

flink-staging/flink-table/src/main/scala/org/apache/flink/api/table/codegen/ExpressionCodeGenerator.scala

@@ -409,7 +409,7 @@ abstract class ExpressionCodeGenerator[R](
           """.stripMargin
         } else {
           s"""
-            |$resultTerm = ${childGen.resultTerm}.getTime();
+            |$resultTpe $resultTerm = ${childGen.resultTerm}.getTime();
           """.stripMargin
         }
         childGen.code + castCode

flink-staging/flink-table/src/test/java/org/apache/flink/api/java/table/test/CastingITCase.java

@@ -18,6 +18,7 @@
 
 package org.apache.flink.api.java.table.test;
 
+import org.apache.flink.api.java.tuple.Tuple2;
 import org.apache.flink.api.java.tuple.Tuple3;
 import org.apache.flink.api.java.tuple.Tuple4;
 import org.apache.flink.api.table.Table;
@@ -145,5 +146,26 @@ public class CastingITCase extends MultipleProgramsTestBase {
 				"1970-01-17 17:47:53.775\n";
 		compareResultAsText(results, expected);
 	}
+
+	@Test
+	public void testCastDateToStringAndLong() throws Exception {
+		ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
+		TableEnvironment tableEnv = new TableEnvironment();
+
+		DataSource<Tuple2<String, String>> input =
+			env.fromElements(new Tuple2<>("2011-05-03 15:51:36.000", "1304437896000"));
+
+		Table table =
+			tableEnv.fromDataSet(input);
+
+		Table result = table
+			.select("f0.cast(DATE) AS f0, f1.cast(DATE) AS f1")
+			.select("f0.cast(STRING), f0.cast(LONG), f1.cast(STRING), f1.cast(LONG)");
+
+		DataSet<Row> ds = tableEnv.toDataSet(result, Row.class);
+		List<Row> results = ds.collect();
+		String expected = "2011-05-03 15:51:36.000,1304437896000,2011-05-03 15:51:36.000,1304437896000\n";
+		compareResultAsText(results, expected);
+	}
 }
 

flink-staging/flink-table/src/test/scala/org/apache/flink/api/scala/table/test/CastingITCase.scala

@@ -105,4 +105,21 @@ class CastingITCase(mode: TestExecutionMode) extends MultipleProgramsTestBase(mo
     TestBaseUtils.compareResultAsText(results.asJava, expected)
   }
 
+  @Test
+  def testCastDateToStringAndLong {
+    val env: ExecutionEnvironment = ExecutionEnvironment.getExecutionEnvironment
+    val ds = env.fromElements(("2011-05-03 15:51:36.000", "1304437896000"))
+    val result = ds.toTable
+      .select('_1.cast(BasicTypeInfo.DATE_TYPE_INFO).as('f0),
+        '_2.cast(BasicTypeInfo.DATE_TYPE_INFO).as('f1))
+      .select('f0.cast(BasicTypeInfo.STRING_TYPE_INFO),
+        'f0.cast(BasicTypeInfo.LONG_TYPE_INFO),
+        'f1.cast(BasicTypeInfo.STRING_TYPE_INFO),
+        'f1.cast(BasicTypeInfo.LONG_TYPE_INFO))
+      .toDataSet[Row]
+      .collect
+    val expected = "2011-05-03 15:51:36.000,1304437896000," +
+      "2011-05-03 15:51:36.000,1304437896000\n"
+    TestBaseUtils.compareResultAsText(result.asJava, expected)
+  }
 }