Fixes 649 to add support for HOUR, MINUTE, SECOND date literals and support for identifiers as the interval parameter. (#756)

Author: thebiguno

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -140,7 +140,7 @@ TOKEN: /* SQL Keywords. prefixed with K_ to avoid name clashes */
 |   <K_CROSS:"CROSS">
 |   <K_CURRENT: "CURRENT">
 |   <K_DATETIMELITERAL : ("DATE" | "TIME" | "TIMESTAMP") >
-|   <K_DATE_LITERAL : ( "YEAR" | "MONTH" | "DAY" ) >
+|   <K_DATE_LITERAL : ( "YEAR" | "MONTH" | "DAY" | "HOUR" | "MINUTE" | "SECOND" ) >
 |   <K_DEFERRABLE : "DEFERRABLE">
 |   <K_DELAYED : "DELAYED">
 |   <K_DELETE:"DELETE">
@@ -2837,7 +2837,7 @@ IntervalExpression IntervalExpression() : {
         [ LOOKAHEAD(2) (token = <S_IDENTIFIER> | token = <K_DATE_LITERAL>) { interval.setIntervalType(token.image); } ]
     |
         { interval = new IntervalExpression(false); }
-        ( token=<S_LONG> | token=<S_DOUBLE> | token=<S_CHAR_LITERAL> ) 
+        ( token=<S_LONG> | token=<S_DOUBLE> | token=<S_CHAR_LITERAL> | token = <S_IDENTIFIER>)
         { interval.setParameter((signed?"-":"") + token.image); }
         token = <K_DATE_LITERAL> { interval.setIntervalType(token.image); }
     )

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

@@ -3470,6 +3470,21 @@ public void testDateArithmentic5() throws JSQLParserException {
         assertSqlCanBeParsedAndDeparsed("SELECT CASE WHEN CURRENT_DATE BETWEEN (CURRENT_DATE - 1 DAY) AND ('2019-01-01') THEN 1 ELSE 0 END FROM SYSIBM.SYSDUMMY1");
     }
 
+    @Test
+    public void testDateArithmentic6() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT CURRENT_DATE + HOURS_OFFSET HOUR AS NEXT_DATE FROM SYSIBM.SYSDUMMY1");
+    }
+
+    @Test
+    public void testDateArithmentic7() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT CURRENT_DATE + MINUTE_OFFSET MINUTE AS NEXT_DATE FROM SYSIBM.SYSDUMMY1");
+    }
+
+    @Test
+    public void testDateArithmentic8() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT CURRENT_DATE + SECONDS_OFFSET SECOND AS NEXT_DATE FROM SYSIBM.SYSDUMMY1");
+    }
+
     @Test
     public void testNotProblemIssue721() throws JSQLParserException {
         assertSqlCanBeParsedAndDeparsed("SELECT * FROM dual WHERE NOT regexp_like('a', '[\\w]+')");