I'm trying to adding a column into a table whose fields are empty, neither "0" nor "null".
"ALTER TABLE `mytable` ADD COLUMN `newcolumn` INT NOT NULL"
makes all fields "0". I also tried DEFAULT='' option but then the column doesn't even added. So how to achieve really blank fields?
You are adding an INT field. It may be NULL or 0, but it can't be the empty string, since that's a string, and not a number.
You have specified NOT NULL. This means that the fields cannot be null i.e. empty.
If you want "really blank" fields, then change the column specification to:
"ALTER TABLE `mytable` ADD COLUMN `newcolumn` INT NULL"
You can't.
The only valid values for the INTEGER column are numbers and NULL. You cannot simply define DEFAULT '' since '' is already an empty string.
ALTER TABLE `mytable` ADD COLUMN `newcolumn` INT DEFAULT 0
Just tested this and works.
ALTER TABLE `__test` ADD `test_column` INT NULL
echo $column (suppose it retrieves the null field) gives n-u-l-l word or the null constant?
I try this code:
create table test( a int )
insert into test(a) values (1),(2),(3)
ALTER TABLE test ADD b INT NOT NULL DEFAULT 0
