Index: jdbc2/AbstractJdbc2DatabaseMetaData.java
===================================================================
RCS file: /usr/local/cvsroot/pgjdbc/pgjdbc/org/postgresql/jdbc2/AbstractJdbc2DatabaseMetaData.java,v
retrieving revision 1.29
diff -u -r1.29 AbstractJdbc2DatabaseMetaData.java
--- jdbc2/AbstractJdbc2DatabaseMetaData.java	3 Feb 2006 21:10:15 -0000	1.29
+++ jdbc2/AbstractJdbc2DatabaseMetaData.java	22 Mar 2006 08:32:51 -0000
@@ -477,7 +477,8 @@
         ','+EscapedFunctions.MONTH+
         ','+EscapedFunctions.MONTHNAME+','+EscapedFunctions.NOW+
         ','+EscapedFunctions.QUARTER+','+EscapedFunctions.SECOND+
-        ','+EscapedFunctions.WEEK+','+EscapedFunctions.YEAR;
+        ','+EscapedFunctions.WEEK+','+EscapedFunctions.YEAR+
+        ','+EscapedFunctions.TIMESTAMPADD+','+EscapedFunctions.TIMESTAMPDIFF;
     }
 
     /*
Index: jdbc2/EscapedFunctions.java
===================================================================
RCS file: /usr/local/cvsroot/pgjdbc/pgjdbc/org/postgresql/jdbc2/EscapedFunctions.java,v
retrieving revision 1.6
diff -u -r1.6 EscapedFunctions.java
--- jdbc2/EscapedFunctions.java	4 Jun 2005 18:24:08 -0000	1.6
+++ jdbc2/EscapedFunctions.java	22 Mar 2006 08:32:51 -0000
@@ -90,8 +90,23 @@
     public final static String SECOND="second";
     public final static String WEEK="week";
     public final static String YEAR="year";
-    // TODO : timestampadd and timestampdiff
+    // for timestampadd and timestampdiff the fractional part of second is not supported
+    // by the backend
+    public final static String TIMESTAMPADD="timestampadd";
+    public final static String TIMESTAMPDIFF="timestampdiff";
+
+    // constants for timestampadd and timestampdiff
+    public final static String SQL_TSI_DAY="SQL_TSI_DAY";
+    public final static String SQL_TSI_FRAC_SECOND="SQL_TSI_FRAC_SECOND";
+    public final static String SQL_TSI_HOUR="SQL_TSI_HOUR";
+    public final static String SQL_TSI_MINUTE="SQL_TSI_MINUTE";
+    public final static String SQL_TSI_MONTH="SQL_TSI_MONTH";
+    public final static String SQL_TSI_QUARTER="SQL_TSI_QUARTER";
+    public final static String SQL_TSI_SECOND="SQL_TSI_SECOND";
+    public final static String SQL_TSI_WEEK="SQL_TSI_WEEK";
+    public final static String SQL_TSI_YEAR="SQL_TSI_YEAR";
 
+    
     // system functions
     public final static String DATABASE="database";
     public final static String IFNULL="ifnull";
@@ -478,6 +493,79 @@
         return "extract(year from "+parsedArgs.get(0)+")";
     }
     
+    /** time stamp add */
+    public static String sqltimestampadd(List parsedArgs) throws SQLException{
+        if (parsedArgs.size()!=3){
+            throw new PSQLException(GT.tr("{0} function takes three and only three arguments.","timestampadd"),
+                                    PSQLState.SYNTAX_ERROR);
+        }
+        StringBuffer buf = new StringBuffer();
+        buf.append("(").append(EscapedFunctions.constantToInterval(parsedArgs.get(0).toString(),parsedArgs.get(1).toString()))
+        	.append("+").append(parsedArgs.get(2)).append(")");
+        return buf.toString();
+    }
+    
+    private final static String constantToInterval(String type,String value)throws SQLException{
+    	if (SQL_TSI_DAY.equalsIgnoreCase(type))
+    		return "'"+value+" day'";
+    	else if (SQL_TSI_SECOND.equalsIgnoreCase(type))
+    		return "'"+value+" second'";
+    	else if (SQL_TSI_HOUR.equalsIgnoreCase(type))
+    		return "'"+value+" hour'";
+    	else if (SQL_TSI_MINUTE.equalsIgnoreCase(type))
+    		return "'"+value+" minute'";
+    	else if (SQL_TSI_MONTH.equalsIgnoreCase(type))
+    		return "'"+value+" month'";
+    	else if (SQL_TSI_QUARTER.equalsIgnoreCase(type))
+    		return "'3*"+value+" month'";
+    	else if (SQL_TSI_WEEK.equalsIgnoreCase(type))
+    		return "'"+value+" week'";
+    	else if (SQL_TSI_YEAR.equalsIgnoreCase(type))
+    		return "'"+value+" year'";
+    	else if (SQL_TSI_FRAC_SECOND.equalsIgnoreCase(type))
+    		throw new PSQLException(GT.tr("Interval {0} not yet implemented","SQL_TSI_FRAC_SECOND"),
+                    PSQLState.SYNTAX_ERROR);
+    	else throw new PSQLException(GT.tr("Interval {0} not yet implemented",type),
+                PSQLState.SYNTAX_ERROR);
+    }
+    
+    
+    /** time stamp diff */
+    public static String sqltimestampdiff(List parsedArgs) throws SQLException{
+        if (parsedArgs.size()!=3){
+            throw new PSQLException(GT.tr("{0} function takes three and only three arguments.","timestampdiff"),
+                                    PSQLState.SYNTAX_ERROR);
+        }
+        StringBuffer buf = new StringBuffer();
+        buf.append("extract( ").append(EscapedFunctions.constantToDatePart(parsedArgs.get(0).toString()))
+        .append(" from (").append(parsedArgs.get(2)).append("-").append(parsedArgs.get(1)).append("))");
+        return buf.toString();
+    }
+    
+    private final static String constantToDatePart(String type)throws SQLException{
+    	if (SQL_TSI_DAY.equalsIgnoreCase(type))
+    		return "day";
+    	else if (SQL_TSI_SECOND.equalsIgnoreCase(type))
+    		return "second";
+    	else if (SQL_TSI_HOUR.equalsIgnoreCase(type))
+    		return "hour";
+    	else if (SQL_TSI_MINUTE.equalsIgnoreCase(type))
+    		return "minute";
+    	else if (SQL_TSI_MONTH.equalsIgnoreCase(type))
+    		return "month";
+    	else if (SQL_TSI_QUARTER.equalsIgnoreCase(type))
+    		return "quarter";
+    	else if (SQL_TSI_WEEK.equalsIgnoreCase(type))
+    		return "week";
+    	else if (SQL_TSI_YEAR.equalsIgnoreCase(type))
+    		return "year";
+    	else if (SQL_TSI_FRAC_SECOND.equalsIgnoreCase(type))
+    		throw new PSQLException(GT.tr("Interval {0} not yet implemented","SQL_TSI_FRAC_SECOND"),
+                    PSQLState.SYNTAX_ERROR);
+    	else throw new PSQLException(GT.tr("Interval {0} not yet implemented",type),
+                PSQLState.SYNTAX_ERROR);
+    }
+    
     /** database translation */
     public static String sqldatabase(List parsedArgs) throws SQLException{
         if (parsedArgs.size()!=0){
Index: test/jdbc2/StatementTest.java
===================================================================
RCS file: /usr/local/cvsroot/pgjdbc/pgjdbc/org/postgresql/test/jdbc2/StatementTest.java,v
retrieving revision 1.19
diff -u -r1.19 StatementTest.java
--- test/jdbc2/StatementTest.java	1 Feb 2006 18:52:13 -0000	1.19
+++ test/jdbc2/StatementTest.java	22 Mar 2006 08:32:52 -0000
@@ -297,6 +297,10 @@
         assertTrue(rs.next());
         // ensure sunday =>1 and monday =>2
         assertEquals(2,rs.getInt(5));
+        
+        rs = stmt.executeQuery("select {fn timestampdiff(SQL_TSI_DAY,{fn now()},{fn timestampadd(SQL_TSI_DAY,3,{fn now()})})} ");
+        assertTrue(rs.next());
+        assertEquals(3,rs.getInt(1));
     }
     
     public void testSystemFunctions() throws SQLException