Struck in the Query

[sivaprasad adusumalli]

Hi ,

I am new to this forum. I struck in query. In my existing table i have two columns. Those two columns default value is showing as 'null' . but i need to change it as empty. Can any body help on this query. I wrote like this but it's not changing default value from 'null' to empty.

 ALTER table t1 ALTER COLUMN c1 set default 'NOT NULL';

thanks in advance.