CREATE PROCEDURE TEST ()
returns (
    lndata char( 32 )
)
as
declare variable aaa varchar( 500 );
begin
  aaa='SELECT aa.nindex FROM tdata aa 
         WHERE (aa.dcreate BETWEEN ''2007-07-01 00:00:00'' AND ''2007-07-31 23:59:59'') AND 
                   (aa.ntype BETWEEN 1 AND 11) GROUP BY aa.nindex';
for EXECUTE STATEMENT :aaa INTO :lndata
  do begin
    (...)
  end
end

Error Message:
----------------------------------------
Overflow occurred during data type conversion.
conversion error from string "2007-07-31 23:59:59".

UPDATE tData SET dcreate=dcreate

BETWEEN ''2007- 07 - 01 '' AND ''2007- 07 - 31 ''

Error Message:
----------------------------------------
Overflow occurred during data type conversion.
conversion error from string "07/31/2007 23:59:59".

CREATE DOMAIN D_DATETIME AS
TIMESTAMP
----------------------
CREATE TABLE TDATA (
    ...
    DCREATE    D_DATETIME,
    ...
);

UPDATE tdata set dcreate=dcreate