Check an int variable is null or is empty from the Database [duplicate]

Question

I am having a variable which is:

nocustomers = rs.getInt("CUST_TRAN_COUNT");

I would like to perform if it is null or not.

I tried

if (nocustomers ==null)

It showed an error.

How do I solve this?

---

My new modified code is:

try{

    query=" select * from SS_summary where txn_date = to_date ('"+asatdate+"','YYYY-MM-DD') ";
    st = conn.createStatement();
    rs = st.executeQuery(query);

    if (rs.next())
    {   


    nocustomers = rs.getInt("CUST_TRAN_COUNT");

    nocheques =rs.getInt("CHEQ_DELIVERED_MAIN");
    }

    if (rs.wasNull()) {
        out.println("NO DATA FOUND");
        }

%>

Answer 1

int can't be null, because it's a primitive type.

For the same reason ResultSet.getInt() can't return null.

You will need to call ResultSet.wasNull() right after your getInt() call to check if the value was null.

Note that since int can't be null, nocustomer will have a value even if the database value is null. getInt() is defined to return 0 when the DB value is null, so nocustomers will be 0.

Answer 2

At compile time, the java compiler will complain with the following message:

incomparable types: int and <nulltype>
if (nocustomers  == null) {
      ^

That is because you can never do a null check on primitive types. Primitive types are assigned with default values (zero, for integers), if unassigned.

If you want to know if the value read was null, use the ResultSet.wasNull() method instead (after reading your integer value, see JavaDoc link provided):

nocustomers = rs.getInt("CUST_TRAN_COUNT");
if (rs.wasNull()) {
    nocustomers = -1; //Assuming, -1 means NULL.
}