Fix interval literal

Author: Olivier Chédru

src/main/java/org/dhatim/sql/hamcrest/QueryMatchers.java

@@ -273,7 +273,7 @@ public static <T> Matcher<SqlQuery> literalContaining(T value) {
     }
 
     public static <T> Matcher<SqlQuery> intervalLiteral(String value) {
-        return xpath("interval", "//interval_literal/*", orderedAllOf(node("INTERVAL"), literal(value)));
+        return xpath("interval", "//interval_literal/*", literal(value));
     }
 
     public static <T> Matcher<SqlQuery> dateLiteral(String value) {

src/test/java/org/dhatim/sql/hamcrest/QueryMatchersTest.java

@@ -81,6 +81,12 @@ public void testDateLiteral() {
         assertThat(sql("SELECT '2010-10-10'::date"), query(dateLiteral("2010-10-10")));
     }
 
+    @Test
+    public void testIntervalLiteral() {
+        assertThat(sql("SELECT INTERVAL '1 month'"), query(intervalLiteral("1 month")));
+        assertThat(sql("SELECT '1 month'::interval"), query(intervalLiteral("1 month")));
+    }
+
     @Test
     public void testConds() {
         assertThat(sql("SELECT * FROM t1 WHERE col1 = 1"), query(where(equal(column("col1"), literal(1)))));