------------------------------ Commands Entered ------------------------------
CREATE TABLE test_alter_lenghth
( id  INTEGER NOT NULL PRIMARY KEY
, str VARCHAR(80)
);
------------------------------------------------------------------------------
DB20000I  The SQL command completed successfully.

------------------------------ Commands Entered ------------------------------
INSERT INTO test_alter_lenghth
VALUES
  ( 1 , 'abcd' )
, ( 2 , 'efghij' )
, ( 3 , NULL );
------------------------------------------------------------------------------
DB20000I  The SQL command completed successfully.

------------------------------ Commands Entered ------------------------------
SELECT * FROM test_alter_lenghth;
------------------------------------------------------------------------------

ID          STR                                                                             
----------- --------------------------------------------------------------------------------
          1 abcd                                                                            
          2 efghij                                                                          
          3 -                                                                               

  3 record(s) selected.


------------------------------ Commands Entered ------------------------------
ALTER TABLE test_alter_lenghth
ALTER str SET DATA TYPE VARCHAR(6);
------------------------------------------------------------------------------
DB20000I  The SQL command completed successfully.

------------------------------ Commands Entered ------------------------------
SELECT * FROM test_alter_lenghth;
------------------------------------------------------------------------------

ID          STR   
----------- ------
          1 abcd  
          2 efghij
          3 -     

  3 record(s) selected.

------------------------------ Commands Entered ------------------------------
CREATE TABLE test_alter_lenghth
( id  INTEGER NOT NULL PRIMARY KEY
, str VARCHAR(80)
);
------------------------------------------------------------------------------
DB20000I  The SQL command completed successfully.

------------------------------ Commands Entered ------------------------------
INSERT INTO test_alter_lenghth
VALUES
  ( 1 , 'abcd' )
, ( 2 , 'efghij' )
, ( 3 , NULL )
, ( 4 , 'klmn    ' )
;
------------------------------------------------------------------------------
DB20000I  The SQL command completed successfully.

------------------------------ Commands Entered ------------------------------
SELECT t.*
     , LENGTH(str) str_len
  FROM test_alter_lenghth t
;
------------------------------------------------------------------------------

ID          STR                                                                              STR_LEN    
----------- -------------------------------------------------------------------------------- -----------
          1 abcd                                                                                       4
          2 efghij                                                                                     6
          3 -                                                                                          -
          4 klmn                                                                                       8

  4 record(s) selected.


------------------------------ Commands Entered ------------------------------
ALTER TABLE test_alter_lenghth
ALTER str SET DATA TYPE VARCHAR(6);
------------------------------------------------------------------------------
SQL0445W  Value "klmn    " has been truncated.  SQLSTATE=01004

------------------------------ Commands Entered ------------------------------
SELECT t.*
     , LENGTH(str) str_len
  FROM test_alter_lenghth t
;
------------------------------------------------------------------------------

ID          STR    STR_LEN    
----------- ------ -----------
          1 abcd             4
          2 efghij           6
          3 -                -
          4 klmn             6

  4 record(s) selected.