How to find out the null values in table

Question

hi experts,
my version is oracledb10g:
i h'd simple doubts.
for eg:
create table ex1( e varchar2(20));
insert into ex1 (null).
insert into ex1(e)
count will be: 2
i can easily found out the value 'e'.
so my question is:
how can i found out the null values in the table and i want to delete the null values from the table.

Answer 1

ADF 7 wrote:
hi experts,
my version is oracledb10g:
i h'd simple doubts.
for eg:
create table ex1( e varchar2(20));
insert into ex1 (null).
insert into ex1(e)
count will be: 2That depends what you count. If you issue count(*) you are asking Oracle "how many rows are there". If you issue a count(<column_name>) you are asking Oracle "how many not null values of <column_name> are there".
ADF 7 wrote:
i can easily found out the value 'e'.
so my question is:
how can i found out the null values in the table and i want to delete the null values from the table.
delete from <table_name>
where <column_name> is null;Ideally you'd just place a NOT NULL constraint on the column in question, thereby prohibiting NULL values from entering into the system (assuming your business requirement is that the column MUST always have a value).