MySQL compatibility: TIMESTAMPDIFF is now an alias for DATEDIFF.

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

@@ -255,6 +255,7 @@ public class Function extends Expression implements FunctionCall {
         addFunctionNotDeterministic("NOW", NOW, VAR_ARGS, Value.TIMESTAMP);
         addFunction("DATEADD", DATE_ADD, 3, Value.TIMESTAMP);
         addFunction("DATEDIFF", DATE_DIFF, 3, Value.LONG);
+        addFunction("TIMESTAMPDIFF", DATE_DIFF, 3, Value.LONG);
         addFunction("DAYNAME", DAY_NAME, 1, Value.STRING);
         addFunction("DAYNAME", DAY_NAME, 1, Value.STRING);
         addFunction("DAY", DAY_OF_MONTH, 1, Value.INT);

h2/src/test/org/h2/test/testSimple.in.txt

+select timestampdiff(month, '2003-02-01','2003-05-01');
+> 3;
+select timestampdiff(YEAR,'2002-05-01','2001-01-01');
+> -1;
+select timestampdiff(MINUTE,'2003-02-01','2003-05-01 12:05:55');
+> 128885;
 select x from (select *, rownum as r from system_range(1, 3)) where r=2;
 > 2;
 select cast(cast('01020304-0506-0708-090a-0b0c0d0e0f00' as uuid) as binary);