Added ADD_MONTHS functionality

h2/src/main/org/h2/expression/Function.java

@@ -85,7 +85,7 @@ public class Function extends Expression implements FunctionCall {
             XMLATTR = 83, XMLNODE = 84, XMLCOMMENT = 85, XMLCDATA = 86,
             XMLSTARTDOC = 87, XMLTEXT = 88, REGEXP_REPLACE = 89, RPAD = 90,
             LPAD = 91, CONCAT_WS = 92, TO_CHAR = 93, TRANSLATE = 94, ORA_HASH = 95,
-            TO_DATE = 96, TO_TIMESTAMP = 97;
+            TO_DATE = 96, TO_TIMESTAMP = 97, ADD_MONTHS = 98;
 
     public static final int CURDATE = 100, CURTIME = 101, DATE_ADD = 102,
             DATE_DIFF = 103, DAY_NAME = 104, DAY_OF_MONTH = 105,
@@ -300,6 +300,7 @@ public class Function extends Expression implements FunctionCall {
                 0, Value.DATE);
         addFunction("TO_DATE", TO_DATE, VAR_ARGS, Value.STRING);
         addFunction("TO_TIMESTAMP", TO_TIMESTAMP, VAR_ARGS, Value.STRING);
+        addFunction("ADD_MONTHS", ADD_MONTHS, VAR_ARGS, Value.TIMESTAMP);
         // alias for MSSQLServer
         addFunctionNotDeterministic("GETDATE", CURDATE,
                 0, Value.DATE);
@@ -1431,6 +1432,9 @@ public class Function extends Expression implements FunctionCall {
             result = ValueTimestamp.get(ToDate.TO_TIMESTAMP(v0.getString(),
                     v1 == null ? null : v1.getString()));
             break;
+        case ADD_MONTHS:
+            result = ValueTimestamp.get(DateTimeUtils.addMonths(v0.getTimestamp(), v1.getInt()));
+            break;
         case TRANSLATE: {
             String matching = v1.getString();
             String replacement = v2.getString();
@@ -2106,6 +2110,10 @@ public class Function extends Expression implements FunctionCall {
     protected void checkParameterCount(int len) {
         int min = 0, max = Integer.MAX_VALUE;
         switch (info.type) {
+        case ADD_MONTHS:
+            min = 2;
+            max = 2;
+            break;
         case COALESCE:
         case CSVREAD:
         case LEAST:

h2/src/main/org/h2/util/DateTimeUtils.java

@@ -902,4 +902,9 @@ public class DateTimeUtils {
         return dateValue(y, m + 3, (int) d);
     }
 
+    public static Timestamp addMonths(final Timestamp timestamp, final int numberMonths) {
+        timestamp.setMonth(timestamp.getMonth() + numberMonths);
+        return timestamp;
+    }
+
 }

h2/src/test/org/h2/samples/ToDate.java

@@ -38,7 +38,7 @@ public class ToDate {
         Statement stat = conn.createStatement();
 
         stat.execute("create table ToDateTest(id int primary key, start_date datetime, end_date datetime)");
-        stat.execute("insert into ToDateTest values(1, TO_DATE('2015-11-13', 'yyyy-MM-DD'), TO_DATE('2015-12-15', 'YYYY-MM-DD'))");
+        stat.execute("insert into ToDateTest values(1, ADD_MONTHS(TO_DATE('2015-11-13', 'yyyy-MM-DD'), 1), TO_DATE('2015-12-15', 'YYYY-MM-DD'))");
         stat.execute("insert into ToDateTest values(2, TO_DATE('2015-12-12 00:00:00', 'yyyy-MM-DD HH24:MI:ss'), TO_DATE('2015-12-16 15:00:00', 'YYYY-MM-DD HH24:MI:ss'))");
         stat.execute("insert into ToDateTest values(3, TO_DATE('2015-12-12 08:00 A.M.', 'yyyy-MM-DD HH:MI AM'), TO_DATE('2015-12-17 08:00 P.M.', 'YYYY-MM-DD HH:MI AM'))");
         stat.execute("insert into ToDateTest values(4, TO_DATE(substr('2015-12-12 08:00 A.M.', 1, 10), 'yyyy-MM-DD'), TO_DATE('2015-12-17 08:00 P.M.', 'YYYY-MM-DD HH:MI AM'))");

h2/src/test/org/h2/test/db/TestFunctions.java

@@ -49,10 +49,7 @@ import org.h2.store.fs.FileUtils;
 import org.h2.test.TestBase;
 import org.h2.test.ap.TestAnnotationProcessor;
 import org.h2.tools.SimpleResultSet;
-import org.h2.util.IOUtils;
-import org.h2.util.New;
-import org.h2.util.StringUtils;
-import org.h2.util.ToDate;
+import org.h2.util.*;
 import org.h2.value.Value;
 
 /**
@@ -78,6 +75,7 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         deleteDb("functions");
         testToDate();
         testToDateException();
+        testAddMonths();
         testDataType();
         testVersion();
         testFunctionTable();
@@ -1386,6 +1384,7 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         assertEquals(date, ToDate.TO_DATE("02:04 PM", "HH:MI PM"));
 
         date = new SimpleDateFormat("yyyy-MM-dd").parse("1970-12-12");
+        date.setMonth(curMonth);
         assertEquals(date, ToDate.TO_DATE("12", "DD"));
 
         date = new SimpleDateFormat("yyyy-MM-dd").parse("1970-11-12");
@@ -1398,6 +1397,22 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         assertEquals(date, ToDate.TO_DATE("113029", "J"));
     }
 
+    private void testAddMonths() throws ParseException {
+        Date date = new SimpleDateFormat("yyyy-MM-dd").parse("2013-01-29");
+
+        Date expected = new SimpleDateFormat("yyyy-MM-dd").parse("2013-02-29");
+        assertEquals(expected, DateTimeUtils.addMonths(new Timestamp(date.getTime()), 1));
+
+        expected = new SimpleDateFormat("yyyy-MM-dd").parse("2014-01-29");
+        assertEquals(expected, DateTimeUtils.addMonths(new Timestamp(date.getTime()), 12));
+
+        expected = new SimpleDateFormat("yyyy-MM-dd").parse("2012-11-29");
+        assertEquals(expected, DateTimeUtils.addMonths(new Timestamp(date.getTime()), -2));
+
+        expected = new SimpleDateFormat("yyyy-MM-dd").parse("2012-01-29");
+        assertEquals(expected, DateTimeUtils.addMonths(new Timestamp(date.getTime()), -12));
+    }
+
     private void testToCharFromDateTime() throws SQLException {
         deleteDb("functions");
         Connection conn = getConnection("functions");