Tag Archives: null

what is the type of NULL

I was a bit surprised to see a VARCHAR2(0) column in my schema


select column_name, data_type, data_length 
from user_tab_columns 
where table_name='V';
COLUMN_NAME     DATA_TYPE            DATA_LENGTH
--------------- -------------------- -----------
X               VARCHAR2                       0

What’s this datatype? It is the datatype of NULL !!!

SQL> create or replace view v as select null x from dual
View created.
SQL> desc v
VIEW v
 Name              Null?    Type        
 ----------------- -------- ------------
 X                          VARCHAR2(0)