How "Alter" work on changing the type of Null ?

[terenceyuen]

I would like to change the type of Null to NO,what is the command for this?

I've tried this one, but no luck to get it work.

ALTER TABLE claims_summary ALTER COLUMN advance_call_details SET NOT NULL;

 

+----------------------+--------------+------+-----+---------+-------+

| Field | Type | Null | Key | Default | Extra |

+----------------------+--------------+------+-----+---------+-------+

| client_id | int(11) | | | 0 | |

| client_code | varchar(30) | | PRI | | |

| club_id | int(11) | | | 0 | |

| club_code | varchar(30) | | PRI | | |

| yearclaim | int(10) | | PRI | 0 | |

| advance_call | double(16,4) | YES | | 0.0000 | |

| additional_call | double(16,4) | YES | | 0.0000 | |

| supplementary_call | double(16,4) | YES | | 0.0000 | |

| release_call | double(16,4) | YES | | 0.0000 | |

| advance_call_details | varchar(240) | YES | | | |

+----------------------+--------------+------+-----+---------+-------+

[btherl]

The manual is here:

 

http://dev.mysql.com/doc/refman/5.0/en/alter-table.html

[bubblegum.anarchy]

ALTER COLUMN is used only to modify the default value of a column.

 

The entire column definition is required to update the NULL/NOT NULL value of a column, as follows:

 

ALTER TABLE MODIFY advance_call_details varchar(240) NOT NULL DEFAULT 'undefined' COMMENT 'advances call details'

 

[terenceyuen]

ALTER COLUMN is used only to modify the default value of a column.

 

The entire column definition is required to update the NULL/NOT NULL value of a column, as follows:

 

ALTER TABLE MODIFY advance_call_details varchar(240) NOT NULL DEFAULT 'undefined' COMMENT 'advances call details'

 

 

Sorry, can you explain the purpose from the beginning 'undefined' COMMENT 'advances call details' I don't really understand.

PS: I'm using Mysql 3.xx

 

 

 

 

[bubblegum.anarchy]

DEFAULT 'indefined' is the default value assigned to the column if none is provided and COMMENT 'advance call details' is like adding comments in programming code but the comment here is associated to the column and should describe the purpose of the information stored in the column.

[terenceyuen]

ALTER TABLE MODIFY advance_call_details varchar(240) NOT NULL DEFAULT 'undefined'

 

Where can I define the table name "claims_summary" in this syntax??

[bubblegum.anarchy]

ALTER TABLE 
     MODIFY advance_call_details varchar(240) NOT NULL DEFAULT 'undefined',
     MODIFY claims_summary text NOT NULL 

 

FYI: blob/text can not have a default value