fixes #69

src/main/java/net/sf/jsqlparser/expression/IntervalExpression.java

@@ -27,6 +27,7 @@
  */
 public class IntervalExpression implements Expression {
 	private String parameter = null;
+    private String intervalType = null;
 
 	public String getParameter() {
 		return parameter;
@@ -35,10 +36,18 @@ public String getParameter() {
 	public void setParameter(String parameter) {
 		this.parameter = parameter;
 	}
+
+    public String getIntervalType() {
+        return intervalType;
+    }
+
+    public void setIntervalType(String intervalType) {
+        this.intervalType = intervalType;
+    }
 
 	@Override
 	public String toString() {
-		return "INTERVAL " + parameter;
+		return "INTERVAL " + parameter + (intervalType!=null?" " + intervalType:"");
 	}
 
 	@Override

src/main/javacc/net/sf/jsqlparser/parser/JSqlParserCC.jj

@@ -1880,6 +1880,7 @@ IntervalExpression IntervalExpression() : {
 }
 {
 	<K_INTERVAL> token=<S_CHAR_LITERAL> { interval.setParameter(token.image); }
+    [ LOOKAHEAD(2) token = <S_IDENTIFIER> { interval.setIntervalType(token.image); } ]
 	{
 		return interval;
 	}

src/test/java/net/sf/jsqlparser/test/select/SelectTest.java

@@ -1460,6 +1460,11 @@ public void testInterval2() throws JSQLParserException {
 
         assertEquals("'45 MINUTE'", iexpr.getParameter());
     }
+
+    public void testInterval3() throws JSQLParserException {
+        String stmt = "SELECT 5 + INTERVAL '3' day";
+        assertSqlCanBeParsedAndDeparsed(stmt);
+    }
 
     public void testMultiValueIn() throws JSQLParserException {
         String stmt = "SELECT * FROM mytable WHERE (a, b, c) IN (SELECT a, b, c FROM mytable2)";

src/test/java/net/sf/jsqlparser/test/select/SpecialOracleTest.java

@@ -68,7 +68,7 @@ public void testAllSqlsParseDeparse() throws IOException {
         }
 
         LOG.log(Level.INFO, "tested {0} files. got {1} correct parse results", new Object[]{count, success});
-        assertTrue(success>=127);
+        assertTrue(success>=128);
     }
 
     @Test

src/test/resources/net/sf/jsqlparser/test/oracle-tests/interval04.sql

@@ -1 +1 @@
-select interval'20' day - interval'240' hour from dual
+select interval '20' day - interval '240' hour from dual